Genetics Of White Horses Unraveled: One Mutation Makes Ordinary Horses Turn Grey, Then White, Very Young
ScienceDaily (July 23, 2008) - The white horse is an icon for dignity which has had a huge impact on human culture across the world. An international team led by researchers at Uppsala University has now identified the mutation causing this spectacular trait and show that white horses carry an identical mutation that can be traced back to a common ancestor that lived thousands of years ago.
The study is interesting for medical research since this mutation also increases the risk for melanoma.
The great majority of white horses carry a dominant mutation that results in rapid greying with age. A "Grey" horse is born coloured (black, brown or chestnut) but the greying process starts very early in life -- during its first year. These horses are normally completely white by six to eight years of age but the skin remains pigmented. Thus, the process resembles greying in humans but the process is ultrafast in these horses. The research presented now demonstrates that all Grey horses carry exactly the same mutation which must have been inherited from a common ancestor that lived thousands of years ago.
"It is a fascinating thought that once upon a time a horse was born that turned grey and subsequently white and the people that observed it were so fascinated by its spectacular appearance that they used the horse for breeding so that the mutation could be transmitted from generation to generation," says Leif Andersson who led the study. Today about one horse in ten carries the mutation for Greying with age.
It is obvious that humans across the world have greatly valued these white horses as documented by the rich collection of stories and paintings featuring white horses. In the new paper, this admiration is illustrated with a reproduction of a painting from the late 17th century of the Swedish king Karl XI on his white horse Brilliant.
The Grey horse is also very interesting from a medical point of view since the mutation also predisposes for the development of melanoma. About 75% of Grey horses older than 15 years of age have a benign form of melanoma that in some cases develops into a malignant melanoma. Thus, the new study has also offered insight into a molecular pathway that may lead to tumour development.
"We propose that the Grey mutation stimulates growth of melanocytes and that this leads to a premature loss of the melanocyte stem cells needed for hair pigmentation whereas the mutation promotes an expansion of some of the melanocytes causing skin pigmentation," says Leif Andersson.
Domestic animals constitute extraordinary models for evolution of biological diversity, as recognized by Charles Darwin. The white horse is a beautiful illustration of the importance of regulatory mutations as a major underlying mechanism for phenotypic diversity within and between species. The Grey mutation does not change any protein structure but it affects the genetic regulation of two genes. The researchers found that the white horses carry an extra copy of a DNA segment located in one of these genes.
"It is very likely that regulatory mutations like the one we found in these white horses constitute the dominating class of mutations explaining differences between breeds of domestic animals as well as between species like humans and chimpanzee," concludes Leif Andersson.
The paper is published on July 20 on the website of Nature Genetics.
Presidential Water Spaniels
Nobody knows Bo like geneticists know Bo.
The Obamas may have accepted Bo the Portuguese water dog as First Puppy because of the breeds hypoallergenic coat, but the dogs are also the most genetically studied breed in the world.
Thanks to their remarkable history, the dogs have been the source of key insights into the function of certain canine genes, including determining a dogs size and whether it is susceptible to a devastating disease. Those insights also have offered clues to researchers looking into human diseases.
"Dogs have many of the same diseases that humans have. There is great hope these [findings] will translate to humans," said Kevin Chase, senior researcher at the Georgie Project at the University of Utah, which studies Portuguese water dog genetics. (Georgie was a water dog belonging to the projects founder.)
A series of lucky breaks has made the breed ideal for genetic research. First, all American Kennel Club-registered water dogs came from a tiny founding group of about 30 animals starting in the 1930s. That means the amount of genetic variation from animal to animal is small compared with breeds that have many founders.
In addition, the breed standard for water dogs allows for a lot of physical variation. Registered Portuguese water dogs can be big or small. They can have curly hair or wavy. They can be black. They can have bits of white hair, as Bo does.
That variety allows geneticists to look at the genomes of big water dogs vs. small ones, seeking out regions where genetic patterns differ. When they find genes that seem to have something to do with size, researchers can apply that idea to other breeds, from mastiffs to toy poodles, and see if the pattern holds.
Doing just that, geneticists found that small dogs shared a snippet of DNA near the IGF1 gene, which helps control growth, on chromosome 15. They think that snippet suppresses the IGF1 gene, which keeps dogs small.
The next step was to look in that area for genes affecting diseases of growth regulation, such as cancer, said geneticist and cancer researcher Elaine Ostrander, head of the Dog Genome Project at the National Human Genome Research Institute in Bethesda, Md.
"The genes we have found are generally responsible for diseases in humans," she said.
The third lucky break also traces back to those original 30 or so dogs. Owners have worked hard to breed out disease and keep the population going, and along the way they became extremely knowledgeable about genetics and its role in health, said Susan Becker, president of the Portuguese Water Dog Club of Greater Chicagoland.
Intense genetic screening and awareness of lineage has always been a philosophy of the breed in the U.S., Becker said.
"Everybody participates in health screening and there is always someone [at the shows] drawing blood from the dogs," she said. "You get virtually 100% compliance."
When the Georgie Project started asking water dog owners to provide blood samples, pedigree lines, X-rays and even, more recently, to ship their dead pets to Utah for autopsies, many owners agreed to do it, Chase said.
So far, the project has looked at the genomes of more than 1,000 water dogs, has X-rays from 600 and has conducted more than 150 autopsies.
"They have been phenomenally supportive of these efforts," Ostrander said, adding that at one show, owners stood in line to offer samples of their dogs' blood. "We came back with 420 blood samples."
The whole idea to use the Portuguese water dog for genetic research actually came from a breeder, not a scientist, Chase said.
About a dozen years ago, University of Utah soybean geneticist Gordon Lark contacted breeder Karen Miller after his water dog, Georgie, died. Miller, who now lives in Maine, sent Lark a puppy for free and urged him to study the genetics of Addison's disease, a form of which strikes both dogs and people. (President Kennedy famously suffered from it.) The Georgie Project was born.
Miller said she did not know whether the Obamas would be participating in the Georgie Project, but said she planned to send Michelle Obama a T-shirt and an issue of the breeds magazine.
Craigslist Job Opening
My deceased aunt gave my two kids a Cocker Spaniel a few months back. The dog has been a terror and become overwhelming for me. I am a single father raising two young children. I cannot face telling the kids that the dog must go. I have found a good home for the dog, and just need someone to transport the dog, and play the villain.
Premise: You will be the dog walker hired by daddy (me) to walk Skittles. I will introduce you to the kids, and you will tell them you are going to help Skittles get her exercise when Daddy is too busy to walk her. At that point you will walk Skittles to your car and take her to her new family 20 minutes from my place. Then return holding just a leash. The story will be that Skittles broke free of the leash and took off. At this point prepare for crying, things being thrown at you, and possibly cursing. My kids are young and dramatic, they're girls.
Pay will be $500. The job will take roughly 2 hours at best.
This job is ideal for an actor looking to diversify their role base, or someone who genuinely likes to make children cry. Acting experience is a plus, but not necessary. Please inform me of any prior experience in this kind of situation.
The Squirrel Battle
This is the second column in a thought-provoking series about how my dog and I are dumber than a squirrel.
Last week, I explained that despite the fact that I had poured (plainly labeled) birdseed into a (universally recognizable) bird feeder in order to feed (well, duh) birds, a lawless squirrel had invaded. This so intimidated the local birds that they weren't landing in the feeder, though I suppose they might also have been put off by the way my dog and I kept noisily charging out the door to curse at the squirrel.
In the face of this injustice, I felt I had no choice but to deploy advanced human weaponry, using my son's squirt gun to hose down the squirrel and send it scampering. I settled into a chair on the porch, water gun in my lap, a study in vigilance.
And then I got hit with a pine cone.
That's right, a pine cone smacked me on the crown of my head. I thought the tree itself had just dealt an improbable blow - pine cones do fall on their own accord, after all. But when the second one stung my scalp, I looked up and there was the squirrel, eyes glinting, hauling himself up the evolutionary ladder from nut-gatherer to projectile- thrower in one afternoon.
Here's something they should teach you in Special Forces: If you fire a squirt gun straight up at a squirrel that is trying to concuss you, most of the water will cascade back on your face.
The squirrel nearly fell out of the tree, it was laughing so hard. I stomped into the house, yelling at my dog, who was napping in the living room, despite the battle raging in the front yard. He seemed offended to be so rudely awakened, but that's what happens in the military: You always pick on someone of lower rank.
"Go out there, and scare the squirrel away!" I instructed.
He raced outside, his fur an angry ridge on his back but apparently thought my orders had been, "Go to the garage, knock over the trash can, and eat something from it!"
Then I was struck with a brilliant thought: Hey, I was at least as advanced a creature as my rodent adversary, even if it was some sort of ninja squirrel. I went out into the yard and looked up at my enemy, who was now on the flat part of my roof, watching coldly. I picked up a pine cone and tossed it at the squirrel, who immediately withdrew.
"He didn't know I could throw back," I explained to the dog, who gazed at me worshipfully. My pooch might not be good at executing orders, but he's great at sucking up to the boss.
Then the squirrel reappeared at the edge of the roof, the pine cone in its jaws. With a flick of its head, it pitched the pine cone back down at me. My dog snapped into retriever mode, pouncing on the pine cone, racing over to me and dropping it at my feet.
"You have got to be kidding me," I said to the squirrel.
I took aim and fired another shot, though I have to say that as weapons go, pine cones lack a certain ferocity, even though they do sting when they crack you on the head.
"You are so lucky I don't have a hand grenade," I told the squirrel, which was probably true for me, as well.
I tried over and over to hit my target, always missing, and every time it would disappear for a moment, bringing back the pine cone and pitching it down to my dog.
And then it struck me how extraordinary this inter-species game of catch and fetch truly was, and how I had gotten caught up in trying to toss the pine cone softly and accurately enough for the squirrel to snare it midair, as it had learned to do for the dog. Truth be told, I sort of liked the little critter now. The three of us were having fun together.
A few days later, when I picked up more birdseed, I also bought some peanuts for the squirrel.
What the heck - we were on the same team.
Swimming orang-utans spearfishing exploits
Orang-utans have confounded naturalists by learning to swim across rivers and to fish with sticks.
Naturalists were shocked to see the apes swim across a river to gain access to some of their favourite fruits at a conservation refuge on Kaja island in Borneo. Orang-utans were previously thought to be non-swimmers. The wildlife experts were equally surprised to see an orang-utan pick up a tree branch and stun a fish before eating it. Other apes introduced to the island were seen trying to spear fish with sticks after watching fishermen using rods. The naturalists also noted that the apes quickly worked out that it was even easier to steal fish from unattended lines used by the humans on the island. The unexpected behaviour has been captured in photographs published in the book Thinkers of the Jungle - the Orang-utan Report, by Gerd Schuster, Willie Smits and Jay Ullal, of the Borneo Orang-utan Survival Association. The pictures are thought to be the first to show an orang-utan using a tool for hunting. The apes live in Borneo and Sumatra and are regarded by some as second only to humans in intelligence. They are threatened with extinction as their habitats diminish
Pets Are Good For You
Children run less risk of being sensitive to allergens if there is a dog in the house in the early years of their lives, scientists have found.
The conclusion, based on a six-year study of 9,000 children, adds weight to the theory that growing up with a pet trains the immune system to be less sensitive to potential triggers for allergies such as asthma, eczema and hay fever.
The hygiene theory of allergy holds that modern life has simply become too clean, meaning that babies immune systems are not exposed to enough germs to develop normally.
Having a dog provides enough dirt of the right kind, the new German study suggests. But it may be important that baby meets dog early enough to affect the immune system as it develops. Our results show clearly that the presence of a dog in the home during subjects infancy is associated with a significantly low level of sensitisation to pollens and inhaled allergens, said Joachim Heinrich of the National Research Centre for Environmental Health in Munich.
The same protective effect was not seen in children who had frequent contact with dogs but none at home.
Previous studies have suggested that exposure to pets may have a protective effect against allergies but many of these studies were based on retrospective questioning of subjects about their exposure.
The new study did not require anybody to remember anything. The children were followed from birth to the age of six. This is likely to make for more reliable results.
In the European Respiratory Journal, Professor Heinrich and colleagues say that the blood of children raised in households with dogs contained fewer markers for allergy, such as antibodies to pollen, house dust mites, cat and dog dander, and mould spores. But actual experience was rather less encouraging. Those children raised alongside a dog were no less likely to develop asthma or other allergies than were the other children. So while their blood samples suggested they were not susceptible, their experience suggested they were.
It is not crystal clear why this is so, Professor Heinrich said. He hopes that the protective effect may show up later in life and is continuing to follow the childrens progress. Further assessments will be made when they reach the age of 10.
In the meantime, he does not recommend that parents get a puppy. Until we understand the mechanisms underlying this protective effect from dogs, we will not be able to draw any further conclusions or make any recommendations, Dr Heinrich said.
Doctors who specialise in allergy have found advising parents difficult. Where children already have allergies, cats and dogs tend to make them worse by exposing them to allergens from the pets coats.
But more recent evidence has tended to show that early exposure to cats, dogs, and to farm animals is neutral or even protective. Children raised on farms appear to be protected against all sorts of allergens, not just those produced by farm animals.
Other studies similar in design to Professor Heinrichs have produced equivocal findings. Some suggest early exposure to cats increases the risk, others that it diminishes it. Yet others find no effect one way or the other.
But one study published in the Journal of Allergy and Clinical Immunology in 2002 found that asthma symptoms were reduced in homes that owned a dog, and probably also in those that owned a cat.
Dr Guy Marks, of the Institute for Respiratory Medicine in New South Wales, concluded in 2002 that parents should neither be advised to rid their homes of pets, nor acquire them as a prevention against asthma. Further research was needed, he concluded.
Benefits Part 2
A DOG or cat owner spends roughly $10,000 on the care and feeding of his pet over its lifetime. (Dogs cost more per year, but cats make up for it by living longer.) What does he get for this investment?
Surveys indicate that what most pet owners mainly want is companionship, unconditional love and a play pal. In recent years, however, we have also begun to regard pets as furry physicians and four-legged psychotherapists.
The idea that domestic animals are beneficial to human health and happiness has been fueled by books like The Healing Power of Pets: Harnessing the Amazing Ability of Pets to Make and Keep People Happy and Healthy, by the veterinarian Marty Becker, and by news reports claiming that having a dog helps you live longer or that swimming with dolphins can cure autism, bad backs, attention deficit disorder and even cancer. But is there any truth to these claims?
The task of distinguishing hype from reality on this question falls to anthrozoology, the new science of human-animal relationships. In 1980, Erika Friedmann, a scientist at the University of Pennsylvania, found the first evidence that animals might provide medical benefits: a survey of 92 heart attack victims revealed that those who had pets were nearly five times more likely to be alive a year later than those without them.
Since then, research has shown that stroking an animal lowers blood pressure, that AIDS patients living with pets are less depressed and that pet owners have lower cholesterol levels, sleep more soundly, exercise more and take fewer sick days than non-pet owners. Indeed, I have a stack of articles in my office supporting the hypothesis that pets are healthy for us.
Unfortunately, however, I also have another stack of articles, almost as high, showing that pets have either no long-term effects or have even adverse effects on physical and mental health.
A 2006 survey of Americans by the Pew Research Center, for instance, reported that living with a pet did not make people any happier. Similarly, a 2000 Australian study of mortality rates found no evidence that pet owners lived any longer than anyone else. And last year Dutch researchers concluded that companion animals had no effect on their owners physical or mental well-being. Worse, in 2006, epidemiologists in Finland reported that pet owners were more likely than non-pet owners to suffer from sciatica, kidney disease, arthritis, migraines, panic attacks, high blood pressure and depression.
This pattern of mixed results also holds true for the widely heralded notion that animals can cure various physical afflictions. For example, a study of people with chronic fatigue syndrome found that while pet owners believed that interacting with their pets relieved their symptoms, objective analysis revealed that they were just as tired, stressed, worried and unhappy as sufferers in a control group who had no pets. Similarly, a clinical trial of cancer patients undergoing radiation therapy found that interacting with therapy dogs did no more to enhance the participants morale than reading a book did.
As for the presumed curative powers of swimming with dolphins, researchers at Emory University who reviewed the dolphin therapy studies concluded that every one purporting to document positive health effects was methodologically flawed.
Don't get me wrong. I don't mean to disparage animal companionship; pets are central to my life, too. But the truth is that we know little about how pets could affect us biologically, or why a health benefit accrues to some people but not others. Answering these questions will require the same rigorous methods that scientists use to test the effectiveness of drugs and medical procedures.
Despite the importance of pets in our lives, researchers in the health and behavioral sciences have, until recently, largely neglected the study of human-animal relationships. But this is changing. In 2008, the National Institutes of Health (in conjunction with Mars, the corporate giant whose products include pet food) began a multimillion-dollar research initiative that will eventually help separate fact from wishful thinking on how pets influence human health and happiness.
No doubt, the talk in some medical circles of prescribing puppies and kittens for the chronically ill is well intentioned. But until the research is complete, pet lovers should probably keep taking their Lipitor and Prozac.
Sharing
On these taxing days, when we become a defiantly bipartisan nation of whiners convinced that we are handing over to the Internal Revenue Service our blood and sweat and mothers milk, our pound of flesh and firstborn young, maybe its time for a little perspective.
Legions before us have donated all these items and more to the public till, and not just metaphorically speaking, either. Benjamin Franklin was right to equate paying taxes with a deeply organic behavior like dying. It turns out that giving up a portion of ones income for the sake of the tribe is such a ubiquitous feature of the human race that some researchers see it as crucial to our species success. Without ritualized taxation, there would be precious little hominid representation.
Moreover, plenty of nonhuman animals practice the tithers art, too, demanding that individuals remit a portion of their food, labor, comfort or personal fecundity for the privilege of group membership. And just as the I.R.S. depends on threat of audit as much as it does on anybody's sense of civic responsibility, so do other toll-collecting species ensure compliance by meting out swift punishment against tax cheats. For example, Marc Hauser of Harvard University has found that when a rhesus monkey is out foraging and comes upon a source of especially high-quality food, like, say, a batch of ripe coconuts, the monkey is expected to give a characteristic food call to alert its comrades to the find. The bad thing about doing a food call is that it means others will come and take some of the food, said Laurie R. Santos, who studies the primates at Yale University. Yet a monkey who opts to keep mum about its discovery could face worse. Should other group members happen by while the private feast is under way, they will not only claim the food for themselves, but the most dominant among them will also beat the cheater indignantly.
Not everybody is subject to a big macaque attack. Adolescent males that have only recently transferred into the group are not required to issue food alerts. They are, as yet, on probation, and only upon gaining the rights of full citizenship will the young males be expected to shoulder its duties.
The more closely knit an animal society is, and the more interdependent its members, the higher the rate of taxation. Among bell miner birds of Australia, for example, pairs of breeding adults are assisted at the nest by several youthful helpers, usually male. The helpers provision the couple's fledglings with a steady supply of lerp, sugary casings secreted by plant-sucking insects. And though some scientists had wondered whether lerp wasn't basically a junk food, offered up to the young bell miners as much for show as for substance, researchers report in the March issue of Animal Behaviour that lerp is, in fact, as important to the fledglings growth as is the meatier arthropod prey supplied by their parents. By all evidence, the helper birds are honestly paying to stay, trading a valuable currency for the right to remain within the aggressively guarded precincts of a bell miner breeding colony, with the hope of better times and personal propagation opportunities ahead.
Or at least of averting personal injury. Among another Australian species of cooperatively breeding birds, the superb fairy-wren, dominant males notice when their helpers are less than superb about paying their taxes. Should a helper fail to feed and groom the dominant's nestlings, or to give an alarm call on seeing intruders enter the territory, the dominant male will angrily chase, harass and peck at the helper, for up to 26 hours at a time. In the case of the highly social cichlid fish, fear of punishment inspires delinquent helper fish to ostentatiously redouble their contributions to the communal nest, their digging in the sand, their cleaning and fanning of the eggs - rather like politicians who suddenly pony up three years of back taxes for themselves, the nanny and the gardener. If they don't pay their bill, there will be punishment, said Michael Taborsky of the University of Bern, so they try to pre-emptively appease the dominant individuals in the group.
If hope and fear don't guarantee compliance, there's always embarrassment. Vampire bats are famous for their willingness to regurgitate a blood meal to feed fellow bats that are down on their luck. In fact, hiding one's wealth is a problem. A fully fed vampire bat is as bloated as a fraternity water balloon, and the bats appear to rub bellies to see who is in a position to share. It's hard to cheat when your stomach is obviously distended, Dr. Santos said.
It's also hard to cheat when you live in a small band of big-brained, sharp-eyed individuals, as humans did for vast stretches of our past, which may help explain why we are so easily taxed. There's not a human society in the world that doesn't redistribute food to nonrelatives, said Samuel Bowles, director of the behavioral sciences program at the Santa Fe Institute. Whether it's through the state, or the chief, or a rural collective, or some other mechanism, food sharing of large nutritional packages is quite extensive and has been going on for at least 100,000 years of human history. In hunting and foraging cultures, the proportional tax rate is so high, said Dr. Bowles, that even the Swedes would be impressed.
Take the case of the Ache tribe of Paraguay. Hunters bring their bounty back to a common pot. The majority of calories are redistributed, he said. It ends up being something like a 60 percent income tax.
Pastoral and herding societies tend to be less egalitarian than foraging cultures, and yet, here, too, taxing is often used to help rectify extreme inequities. When a rich cattle farmer dies among the Tandroy of southern Madagascar, Dr. Bowles said, The rich person's stock is killed and eaten by everyone, often down to the last head of cattle. That's a 100 percent inheritance tax.
Modern taxes are just a newfangled version of commitment to the group, said David Sloan Wilson of Binghamton University, the result of the invention of money. Yet even with our elaborate, abstracted tax code, fear of public opprobrium remains an impressive motivator. It's expected that powerful, high-status members of society should be contributing more, Dr. Wilson said. If they don't, they won't remain high status for long. And for the fat bats among us who just won't cough up the goods - there's always jail.
Killer Whales
His (Frozen Planet's Doug Allan) account of the time when he filmed killer whales engaging in a new type of predatory behaviour in 2009 for Frozen Planet, is typical.
In 1977, when he was working in the Antarctic, he'd heard vague rumours that the whales were using previously unheard of methods to hunt seals on top of floating icebergs. He had no idea whether it was true or whether it was just one pod of whales that had learnt this behaviour, but the Frozen Planet team spent three weeks traversing the half-frozen waters to find out. They eventually found a pod of killer whales and observed them swimming into the cracked floating ice and sticking their shiny black heads out of the water to spy on the seals lying on top of the ice.
It was not until the pod came across a blubber-rich and slow-moving Weddell seal, however, that Allan knew for certain that they were watching something entirely new. The pod swam away to a distance of about 100 yards, and together they sped towards the iceberg, beating their tails to create a huge wave that broke on top of it, washing the helpless seal into the water, and into their jaws.
"It's one of the most impressively co-ordinated pieces of predation that you could ever see," he says. "How they sort out among themselves how to do it, and why they only ever go for Weddell seals, I don't know. We were in the area for three weeks, and in total we saw them make about 150 waves."
'Depraved' Penguins?
Accounts of unusual sexual activities among penguins, observed a century ago by a member of Captain Scott's polar team, are finally being made public. Details, including "sexual coercion", recorded by Dr George Murray Levick were considered so shocking that they were removed from official accounts. However, scientists now understand the biological reasons behind the acts that Dr Levick considered "depraved".
The Natural History Museum has published his unedited papers. Dr Levick, an avid biologist, was the medical officer on Captain Scott's ill-fated Terra Nova expedition to the South Pole in 1910. He was a pioneer in the study of penguins and was the first person to stay for an entire breeding season with a colony on Cape Adare.
He recorded many details of the lives of adelie penguins, but some of their activities were just too much for the Edwardian sensibilities of the good doctor. He was shocked by what he described as the "depraved" sexual acts of "hooligan" males who were mating with dead females. So distressed was he that he recorded the "perverted" activities in Greek in his notebook.
On his return to Britain, Dr Levick attempted to publish a paper entitled "the natural history of the adelie penguin", but according to Douglas Russell, curator of eggs and nests at the Natural History Museum, it was too much for the times. "He submitted this extraordinary and graphic account of sexual behaviour of the adelie penguins, which the academic world of the post-Edwardian era found a little too difficult to publish," Mr Russell said. The sexual behaviour section was not included in the official paper, but the then keeper of zoology at the museum, Sidney Harmer, decided that 100 copies of the graphic account should be circulated to a select group of scientists.
Mr Russell said they simply did not have the scientific knowledge at that time to explain Dr Levick's accounts of what he termed necrophilia. "What is happening there is not in any way analogous to necrophilia in the human context," Mr Russell said. "It is the males seeing the positioning that is causing them to have a sexual reaction. "They are not distinguishing between live females who are awaiting congress in the colony, and dead penguins from the previous year which just happen to be in the same position."
Only two of the original 100 copies of Dr Levick's account survive. Mr Russell and colleagues have now published a re-interpretation of Dr Levick's findings in the journal Polar Record. Mr Russell described how he had discovered one of the copies by accident. "I just happened to be going through the file on George Murray Levick when I shifted some papers and found underneath them this extraordinary paper which was headed 'the sexual habits of the adelie penguin, not for publication' in large black type. "It's just full of accounts of sexual coercion, sexual and physical abuse of chicks, non-procreative sex, and finishes with an account of what he considers homosexual behaviour, and it was fascinating." The report and Dr Levick's handwritten notes are now on display at the Natural History Museum for the first time. Mr Russell believes they show a man who struggled to understand penguins as they really are.
"He's just completely shocked. He, to a certain extent, falls into the same trap as an awful lot of people in seeing penguins as bipedal birds and seeing them as little people. They're not. They are birds and should be interpreted as such
Clever Corvids
Some parents boast of their child’s reading ability, others of their position in the last maths exam. But few would think of telling compatriots at the schoolgate about little Johnny’s exceptional performance compared with woodland birds. Until now, perhaps.
Because, according to a paper published yesterday, when given a classic problem from Aesop’s Fables, most children younger than eight were no better at solving it than an average jay.
Researchers at Cambridge University presented children and Eurasian jays with a tube half-filled with water, and a treat floating on the top. The only way to get to the treat – in the children’s case a token for getting a sticker, in the jays’ case food – was by dropping in marbles until the water level rose.
The task mirrors an Aesop’s fable long considered just a nice story, rather than a genuine observation of corvid intelligence, in which a thirsty crow, also a member of the corvid family, dropped pebbles into a half-empty pitcher until it could reach the water with its beak.
Like the tortoise and the hare in Aesop’s more famous fable, the children do eventually catch up; after the age of eight they begin reliably to outperform jays, most notably in a harder variant of the test in which two tubes are connected by a u-bend hidden under the table. In this case the correct solution is to put a stone in the wrong tube, which leads to a water level rise in the one containing the treat.
Even this victory for human intelligence might not be of much comfort for those parents who like to think that their progeny is a future Einstein, rather than an averagely-intelligent crow. Because one of the scientists behind the study hypothesised that the reason jays perform poorly on the u-bend test is because, without knowing the tubes are linked, the solution appears to disobey the laws of physics. “They have already learnt what is and is not possible in world,” said Lucy Cheke.
Children, conversely, have no such scruples about fluid mechanics and apply trial and error. “Children still believe in magic, children are incredibly credulous,” adds Ms Cheke. In other words, the only reason jays are less good at solving the problem could be because they are more rational.
“It’s an interesting developmental stage for children,” says Ms Cheke of this difference in jay-children cognition. “They are more open then to investigating cause and effect. Up to a late age they are willing to give the world the benefit of the doubt.”
The study, published in PLoS One, is just the latest research to investigate the intelligence of members of the corvid family. Past work has shown that crows can recognise the faces of people they dislike, could well possess self-awareness, and will move caches of food if they think another crow has spotted where they hid it.
Could another explanation for the disparity simply be though that, as the evidence from Aesop’s fables attests, putting marbles in jars is a skill to which for some reason corvids are particularly well-attuned?
Ms Cheke, who is studying for a PhD in experimental psychology, thinks not. “On every single experiment we do,” she says, “the crows amaze us.” Eight year old children, conversely, do not.
Future Planning
Birds, like humans, worry about the future and act accordingly, a study has shown.
Conscious planning had been considered a purely human trait, but a series of experiments has shown that a species of jay does it too.
Unlike grey squirrels, which are thought to bury nuts instinctively, the western scrub-jay is able to work out when it is likely to face food shortages and will hoard to avert hunger.
Scrub-jays, a North American species similar to Britain’s native jay, were shown to start hoarding when they realised that they would otherwise go without breakfast the following day. It is the first time that a nonprimate species has been demonstrated to have grasped the concept of time and being able to imagine the future.
The findings, published in Nature, come a month after a study revealed that baboons can plan food-hunting expeditions like a shopping trip, knowing which plants to head for first in the morning before other animals eat all the fruit.
Professor Nicky Clayton, who led the bird study at the University of Cambridge, said: “Future planning is a complex cognitive skill that was thought to be unique to humans. The present study shows that scrub-jays can plan what and where to cache for tomorrow’s breakfast.”
Other bird behaviour such as nest-building, migration and hiding nuts to eat over winter have yet to be demonstrated to involve forethought. These are regarded, Professor Clayton said, as instinctive behaviours. “Most of these are automatic responses triggered by a seasonal cue, rather than requiring any forethought. This paper on scrub-jays describes the first evidence of an animal planning for a motivational need that will not occur until tomorrow.”
To assess the ability of the western scrub-jay, Aphelocoma californica, to plan, breakfast was given or withheld on alternate days. The birds were given access to different compartments depending on whether they were being given pine nuts or nothing. When given the nuts the jays put some into the compartment where they knew they would face the prospect of getting no breakfast the following day.
To confirm the hoarding took place on the basis of imagining the future rather than the association of hunger with one of the compartments, a second experiment provided dog food and peanuts on alternate days. The birds quickly worked out that to assure themselves of a varied diet they needed to hoard dog food in the peanut compartment and vice versa.
How Does a Caterpillar Turn into a Butterfly?
As children, many of us learn about the wondrous process by which a caterpillar morphs into a butterfly. The story usually begins with a very hungry caterpillar hatching from an egg. The caterpillar, or what is more scientifically termed a larva, stuffs itself with leaves, growing plumper and longer through a series of molts in which it sheds its skin. One day, the caterpillar stops eating, hangs upside down from a twig or leaf and spins itself a silky cocoon or molts into a shiny chrysalis. Within its protective casing, the caterpillar radically transforms its body, eventually emerging as a butterfly or moth.
But what does that radical transformation entail? How does a caterpillar rearrange itself into a butterfly? What happens inside a chrysalis or cocoon?
First, the caterpillar digests itself, releasing enzymes to dissolve all of its tissues. If you were to cut open a cocoon or chrysalis at just the right time, caterpillar soup would ooze out. But the contents of the pupa are not entirely an amorphous mess. Certain highly organized groups of cells known as imaginal discs survive the digestive process. Before hatching, when a caterpillar is still developing inside its egg, it grows an imaginal disc for each of the adult body parts it will need as a mature butterfly or moth—discs for its eyes, for its wings, its legs and so on. In some species, these imaginal discs remain dormant throughout the caterpillar's life; in other species, the discs begin to take the shape of adult body parts even before the caterpillar forms a chrysalis or cocoon. Some caterpillars walk around with tiny rudimentary wings tucked inside their bodies, though you would never know it by looking at them.
Once a caterpillar has disintegrated all of its tissues except for the imaginal discs, those discs use the protein-rich soup all around them to fuel the rapid cell division required to form the wings, antennae, legs, eyes, genitals and all the other features of an adult butterfly or moth. The imaginal disc for a fruit fly's wing, for example, might begin with only 50 cells and increase to more than 50,000 cells by the end of metamorphosis. Depending on the species, certain caterpillar muscles and sections of the nervous system are largely preserved in the adult butterfly. One study even suggests that moths remember what they learned in later stages of their lives as caterpillars.
Miniature Animals
WALKING back to camp as night fell in Papua New Guinea, Christopher Austin heard a high-pitched, insect-like call coming from the forest floor. He and his companions were there to hunt for new species, so they started searching through the leaf litter.
"But we didn't find anything," says Austin. "We repeatedly did that during the night and weren't able to find out what was making the call. So we ended up just grabbing a whole handful of leaf litter and throwing it into a plastic bag."
Back in camp, with the benefit of better lighting, they slowly went through their haul. It soon became clear why they hadn't been able to find anything out in the rainforest. The creatures that were making the noise were just 7.7 millimetres long. Yet they were not insects but fully grown frogs. "It was obvious that they were adult male frogs, as they were calling to attract a mate," says Austin.
This minute amphibian, found in 2009, is the latest in a string of miniature vertebrates discovered in the past few years. The discoveries have sparked something of a race to find the world's smallest - and although they had no idea at the time, Austin's frog is a leading contender for that title. It could well be smaller than the previous record holder, a tiny freshwater carp from Sumatra in Indonesia described in 2006.
So are there even smaller vertebrates out there waiting to be found? What are the limits on how small a vertebrate can get? And what made these animals so small in the first place?
Many ordinary-sized species, from monkeys to deer, are still being discovered each year, so it is perhaps not surprising that the most diminutive vertebrates have eluded us for so long. The recent rash of discoveries might be partly due to growing awareness of their existence, and partly to new tools. "I used my digital camera as an impromptu microscope, allowing me to quickly recognise this frog as a distinct species," says Austin, who is based at Louisiana State University in Baton Rouge.
Back in the lab, DNA analysis often reveals that very similar looking animals are separate species. And we know the smallest fish were slipping through the net; when a couple of ichthyologists from Singapore happened to use a finer mesh, they started catching miniature fish. Other collectors soon followed suit.
Whatever the reasons, the discoveries are coming in thick and fast. In most groups, from fish and frogs to lizards and snakes, biologists have now found examples of extreme miniaturisation.
Different factors may have driven the evolution of different kinds of animals. Many of the tiny fish live in swamps, for instance, and it is thought their size enables them to survive in small pools during dry periods.
In the case of the frogs, they may have evolved simply because there was a niche available for a tiny predator. "We think one of the major driving factors in the evolution of small body size in these frogs is an abundance of really, really small prey, like mites in the leaf litter that aren't being preyed on heavily by anything else," says Austin. "That food resource, that guild, that ecological niche is something that has caused the independent miniaturisation of frogs throughout the world."
This may help explain why most miniature vertebrates are found on islands rather than on continents. "Not everything makes it out to an island," says Blair Hedges, an evolutionary biologist at Penn State University, whose work in the Caribbean has resulted in the discovery of some of the smallest vertebrates there are. "That means there are open niches and the species that do make it out can expand their ecological space a bit more than they normally would on the continent," he says. "Sometimes that means being really small."
Missing bones
The simplest way to become small is to stop growing earlier. The tiniest animals go a step further: they often stop developing early too, meaning some adult features never form. Mini frogs, for instance, have a somewhat simplified skeleton, probably because bones that appear late in development in larger species never form. "With really small frogs you often get a reduction in the number of digits on the hands and feet," says Christopher Raxworthy, a herpetologist at the American Museum of Natural History in New York, who has helped discover several species of diminutive frogs in Madagascar.
Some of these frogs also bypass one or more steps during early development. Many are "direct developers", that's to say, they skip the tadpole stage entirely and hop straight out of the egg. This may be because they live in environments where there isn't a lot of standing water and the aquatic stage is very dangerous, especially for animals that produce few offspring.
The story is similar for the Sumatran carp described in 2006. They look somewhat like fish larvae, but features such as the presence of eggs in females show they are indeed fully grown adults. When Ralf Britz, an ichthyologist at the Natural History Museum in London, studied their skeletons, he found that compared with close relatives these tiny fish have dozens of bones missing. Most of them are bones that normally appear late on in development, making the fish another example of so-called developmental truncation.
However, midget fish aren't just larvae whose development has frozen. Many have also evolved unique features, such as the male mini-carp's bizarrely modified pelvic fins, which have been transformed into two drumstick-shaped appendages with various hooks and flanges attached. "When I saw them I couldn't really believe my eyes," says Britz. They are unlike anything found in any of the other 3000 or so members of the carp family.
In rare footage of the mating ritual of these fish captured by an amateur aquarist, the male actually seems to use these appendages like drumsticks, flipping upside down to rap out a rhythm on the underside of a floating leaf. This may play a role in attracting the female, says Britz, but nobody has yet looked at their precise function.
Britz thinks the fishes' truncated development opened up new evolutionary possibilities. "Becoming larval has given them more freedom developmentally to do things with their skeleton that others cannot do," he says. It's like building a house. "The more floors you have the less freedom you have to put something on top, but if you go all the way back to the foundation stage then you can do whatever you want."
There is a limit to how much a body can shrink, though. Many of the constraints derive from the fact that for any given shape, the ratio of surface area to volume increases with decreasing size. This is a major issue for warm-blooded birds and mammals: the smaller they get, the faster they lose heat, so they have to generate heat faster to compensate. Minute birds and mammals push their metabolism to the absolute limits. "The classic evidence of this size limitation is in the smallest shrews, where they are constantly eating to renew the energy that is being rapidly lost through their skin," says Hedges.
This is why the smallest recorded bird, the 30-millimetre-long bee hummingbird of Cuba, and the smallest known mammal, the 40-mm Etruscan pygmy shrew found across Europe, north Africa and south-east Asia, are much larger than the smallest known reptile, a dwarf gecko from the Caribbean that measures just 14 mm from snout to anus. An impossibly cute chameleon from Madagascar was hailed as a contender for the title of tiniest reptile earlier this year, but Hedges says it is a fraction longer than the gecko, which he and a colleague discovered.
While heat loss isn't an issue for cold-blooded creatures, water loss is. This is a special problem for amphibians, says Raxworthy. "If a really tiny frog gets out into dry air it could dry out in a matter of minutes," he says.
This was something Austin was careful to avoid when testing the jumping abilities of his pint-size Papua New Guinean frogs. "With this incredibly porous skin and this really large surface area to volume ratio, it makes desiccation a real issue." This is probably why the frogs stay in moist leaf litter.
Fish would appear to have things easier. Being cold-blooded and aquatic, heat loss and desiccation are not a problem. There are other constraints that kick in at such sizes, though. Losing a few bones here or there might not make much difference to a very small animal, but all its parts still have to work. It still has to be able to see and hear and so on. And there are fundamental limits on how far organs can be scaled down. One is that organs are made of cells, a certain number of which are needed to make complex organs like brains and eyes. The upshot is that an organ in a small animal is usually larger relative to its size than in a big animal.
As vertebrates get really petite, then, it becomes increasingly tricky to fit everything they need inside the body - especially offspring. "You can't have half a baby. The only way you could go is to have smaller offspring but smaller offspring would struggle to survive," Hedges says. So a reduction in size leads to reduction in the number of offspring.
This is evident for the world's smallest snake, the 100-mm-long Barbados threadsnake described by Hedges in 2008. The female produces only one egg at a time, and even then it's a squash, taking up half of the body cavity. "The female has to fill up this tubular spaghetti-shaped body cavity with her offspring," says Hedges. "The egg that's laid is this long sausage that's 10 times as long as it is wide."
Smallest of them all?
In fact, most miniature amphibians, reptiles and mammals that go in for internal fertilisation have room only for one, relatively large offspring, a clear indication that they are about as little as they can be.
Body shape, then, may account for the fact that the smallest known amphibians are shorter than their reptile counterparts, despite the problem of water loss. "The frog is more like a sphere with limbs," says Hedges, and this makes it easier to pack in the organs while still leaving room for an egg.
All these considerations suggest that while there might be even smaller vertebrates still out there waiting to be discovered, they are unlikely to be much smaller. In the meantime, biologists are still arguing about which of the known vertebrates holds the record.
Frogs have an obvious advantage in this competition. "Frogs don't have tails. Fish do," says Austin. With the smallest of his specimens from Papua New Guinea measuring just 7 mm from snout to anus, he says it surely beats Britz's carp, where the shortest mature individual was 7.9 mm long from its snout to start of the tail fin, which is how ichthyologists measure body length.
Britz brushes aside this amphibian challenge. This is not comparing like with like, he says. "If I were to use the amphibian metric [of snout to anus] we would have the smallest by far," says Britz. "It would be less than 5 millimetres."
Austin is having none of it. "Smallest clearly refers to a length measurement and tails count in measurement of fish length as any angler knows," he says. "This is no fault of the frogs, fish or scientists. Rather it is a biological and anatomical reality."
Still, perhaps we should wait a few years before awarding any prizes. The frog might be least, but it's probably not the last.
I'm A Girl
Who says males can't multitask? Cuttlefish can dupe rival males into thinking they're girls, even while actively courting a female.
Cuttlefish are famed for their ability to change colour for communication purposes. Male mourning cuttlefish (Sepia plangon) normally display pulsating stripes, whereas females are mottled.
But the males aren't averse to a spot of cross-dressing, says Culum Brown of Macquarie University in Sydney, Australia.
Brown's team observed wild cuttlefish in Sydney harbour for six years. Whenever a male was courting a female, and there was a rival male nearby, the courting male started lying. He displayed male colours on the side facing the female, but female colours on the other side to dupe the rival and prevent him from interfering.
Males did not do this when there were two rivals present, presumably because it would be too difficult to deceive both of them. That suggests the animals were trying to avoid being caught lying – something that requires a high level of social intelligence.
It's not the first time cuttlefish have been seen using deceptive displays. Male giant cuttlefish pretend to be female to sneak into other males' harems.
Rats
If you thought Frankenstorm would rid Gotham of its vermin, think again. Rodents are as resilient as cockroaches. Winston Ross reports.
Whither the Rattus norvegicus?
It’s a natural question, to wonder if Frankenstorm that swamped New York City on Monday night might depart with some silver-lined clouds—namely, that Hurricane Sandy either drowned the city’s inestimable millions of hearty Norway rats or washed them off the island altogether.
Even Brooklyn’s own Bob Sullivan, author of the widely renowned book Rats, who has spent as much time thinking about rats as anyone who doesn’t pick up trash could possibly be expected to; even he had to stop and ponder it for a second: “Well, the streets do seem a lot cleaner, in some places,” he told The Daily Beast on Tuesday. But the rodent expert quickly came to his senses. There’s a reason rats are so often compared to humans (like a “rat in a cage”)—they’re resilient, like we are. And there’s also a reason for the myriad water-related rat metaphors in the vernacular (“rats fleeing a sinking ship”): they’re particularly good swimmers.
“They’re going to be like us,” Sullivan said. “Get washed out, try to come back in.”
People keep asking him about the tunnels, he said, hoping maybe rats will get sucked out of the city via the Holland Tunnel, for example. But that’s based on the assumption that tunnels are full of rats—a misperception, Sullivan said. “People think where it’s dark, they can’t see anything, there are rats there,” he said. “But the number-one thing rats want to be around is people, people who drop garbage on the ground.”
Sure, Sandy caused rat casualties: drowning, getting crushed by floating taxicabs. But most of the rodents will just relocate, said Rick Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Middlebrook, N.Y. “People and rats together have a corner on the adaptability market,” Ostfeld told The Daily Beast. “We’re amazingly resilient when it comes to these kinds of disasters, and so are our furry little friends. They just do it differently than we do.”
That’s in part because of rats’ somewhat uncanny ability to swim. They’re not particularly built for it, Ostfeld notes, with no webbed feet or muskrat-flat tail to be used as a side-to-side propulsion instrument, and they’re mostly a terrestrial mammal. But, like humans, they’re jacks-of-all-trades. “They have an all-purpose body design,” Ostfeld said. “They’re pretty good at climbing, swimming, and running around on land.”
Animals truly threatened by a hurricane are “specialists,” Ostfeld said, leading long, slow-paced lives. Were New York full of otters, bobcats, foxes, and coyotes, there might be massive die-offs from an intense flood. Rats, on the other hand, “Live fast, die young, breed explosively, and fill up the world with more rats.”
Sandy may actually help the vermin spread diseases, as a matter of fact. It’s a fair wager that most rat populations are skittering around with one or more nasty ailments: leptospirosis, typhus, salmonella, or hantavirus, to name a few. But they don’t carry all of those diseases at once, and those pathogens and viruses are often concentrated among certain populations. What a flood can do is scatter rats (and their food: garbage), relocating them and allowing them to distribute their particular plagues to other rats and, by extension, to people.
“People and rats together have a corner on the adaptability market,” says disease ecologist Rick Ostfeld. There are badger populations in the United Kingdom, for example, that represent the main source of tuberculosis bacteria that have proven a scourge in the cattle industry there. “If there’s tuberculosis in the cows, European badgers are usually the main source of infection,” Ostfeld said.
Farmers have in the past tried hunting those badgers to knock back the threat, only to find that it causes them to disperse and transmit the disease to a wider population. Same with some of the deadly viruses bats harbor, especially the large breed known as “flying foxes.” Past attempts to disrupt their populations has led to outbreaks of viral diseases in people and horses in Australia.
So, sorry, New York, but Sandy isn’t likely to have put much of a dent in the city’s rat problem. If anything, the hurricane may have made things worse.
Cats Are Killers
For all the adorable images of cats that play the piano, flush the toilet, mew melodiously and find their way back home over hundreds of miles, scientists have identified a shocking new truth: cats are far deadlier than anyone realized.
In a report that scaled up local surveys and pilot studies to national dimensions, scientists from the Smithsonian Conservation Biology Institute and the Fish and Wildlife Service estimated that domestic cats in the United States — both the pet Fluffies that spend part of the day outdoors and the unnamed strays and ferals that never leave it — kill a median of 2.4 billion birds and 12.3 billion mammals a year, most of them native mammals like shrews, chipmunks and voles rather than introduced pests like the Norway rat.
The estimated kill rates are two to four times higher than mortality figures previously bandied about, and position the domestic cat as one of the single greatest human-linked threats to wildlife in the nation. More birds and mammals die at the mouths of cats, the report said, than from automobile strikes, pesticides and poisons, collisions with skyscrapers and windmills and other so-called anthropogenic causes.
Peter Marra of the Smithsonian Conservation Biology Institute and an author of the report, said the mortality figures that emerge from the new model “are shockingly high.”
“When we ran the model, we didn’t know what to expect,” said Dr. Marra, who performed the analysis with a colleague, Scott R. Loss, and Tom Will of the Fish and Wildlife Service. “We were absolutely stunned by the results.” The study appeared Tuesday in the journal Nature Communications.
The findings are the first serious estimate of just how much wildlife America’s vast population of free-roaming domestic cats manages to kill each year.
“We’ve been discussing this problem of cats and wildlife for years and years, and now we finally have some good science to start nailing down the numbers,” said George H. Fenwick, the president and chief executive of the American Bird Conservancy. “This is a great leap forward over the quality of research we had before.”
In devising their mathematical model, the researchers systematically sifted through the existing scientific literature on cat-wildlife interactions, eliminated studies in which the sample size was too small or the results too extreme, and then extracted and standardized the findings from the 21 most rigorous studies. The results admittedly come with wide ranges and uncertainties.
Nevertheless, the new report is likely to fuel the sometimes vitriolic debate between environmentalists who see free-roaming domestic cats as an invasive species — superpredators whose numbers are growing globally even as the songbirds and many other animals the cats prey on are in decline — and animal welfare advocates who are appalled by the millions of unwanted cats (and dogs) euthanized in animal shelters each year.
All concur that pet cats should not be allowed to prowl around the neighborhood at will, any more than should a pet dog, horse or potbellied pig, and that cat owners who insist their felines “deserve” a bit of freedom are being irresponsible and ultimately not very cat friendly. Through recent projects like Kitty Cams at the University of Georgia, in which cameras are attached to the collars of indoor-outdoor pet cats to track their activities, not only have cats been filmed preying on cardinals, frogs and field mice, they have also been shown lapping up antifreeze and sewer sludge, dodging under moving cars and sparring violently with much bigger dogs.
“We’ve put a lot of effort into trying to educate people that they should not let their cats outside, that it’s bad for the cats and can shorten the cats’ lives,” said Danielle Bays, the manager of the community cat programs at the Washington Humane Society.
Yet the new study estimates that free-roaming pets account for only about 29 percent of the birds and 11 percent of the mammals killed by domestic cats each year, and the real problem arises over how to manage the 80 million or so stray or feral cats that commit the bulk of the wildlife slaughter.
The Washington Humane Society and many other animal welfare organizations support the use of increasingly popular trap-neuter-return programs, in which unowned cats are caught, vaccinated, spayed and, if no home can be found for them, returned to the outdoor colony from which they came. Proponents see this approach as a humane alternative to large-scale euthanasia, and they insist that a colony of neutered cats can’t reproduce and thus will eventually disappear.
Conservationists say that, far from diminishing the population of unowned cats, trap and release programs may be making it worse, by encouraging people to abandon their pets to outdoor colonies that volunteers often keep lovingly fed.
“The number of free roaming cats is definitively growing,” Dr. Fenwick of the bird conservancy said. “It’s estimated that there are now more than 500 T.N.R. colonies in Austin alone.”
They are colonies of subsidized predators, he said, able to survive in far greater concentrations than do wild carnivores by dint of their people-pleasing appeal. “They’re not like coyotes, having to make their way in the world,” he said.
Yet even fed cats are profoundly tuned to the hunt, and when they see something flutter, they can’t help but move in for the kill. Dr. Fenwick argues that far more effort should be put into animal adoption. “For the great majority of healthy cats,” he said, “homes can be found.” Any outdoor colonies that remain should be enclosed, he said. “Cats don’t need to wander hundred of miles to be happy,” he said.
The True Nature of Cats
The domestic cat is easily the world's most popular pet, outnumbering dogs by as many as three to one. This popularity is undoubtedly helped by the fact that cats are simultaneously affectionate and self-reliant. They need virtually no training. They groom themselves. They can be left alone without pining for their owners, but most nonetheless greet us affectionately when we get home. In a word, they are convenient.
Even so, cats remain aloof and inscrutable. Dogs tend to be open, honest and biddableMovie Camera. Cats, on the other hand, demand we accept them on their terms, but never quite reveal what those terms might be.
Will we ever know? I'm convinced that we will. I've shared my home with quite a few cats, but I don't feel that this has taught me very much about what they are really like. Rather, it is science that has begun to reveal the cat's true nature, especially in regard to their relationship with humans. This is a good time to take stock of what we know, and how we can use our knowledge to improve cats' daily lives.
Cats and humans go back a long way. DNA evidence identifies the pet cat's ancestor as the Arabian wildcat Felis silvestris lybica, and places its origins somewhere between 10,000 and 15,000 years ago in the Middle East.
It is likely that the first people to tame wildcats were the Natufians, who inhabited the Levant from about 13,000 to 10,000 years ago and are widely regarded as the inventors of agriculture. As such, they were also the first people to be bedevilled by a new pest – the grain-loving house mouse. Wildcats probably moved in to exploit this new resource. Realising how useful this was – cats, after all, had no interest in eating grain – people must have encouraged them to hang around.
These were not pet cats as we know them. They would have been more like today's urban foxes, able to adapt to a human environment while retaining their essential wildness.
Of course, the cat's other qualities would not have gone unnoticed. Their appealing features, soft fur and ability to learn to become affectionate toward us led to their adoption as pets. The cat gradually insinuated itself into homes and hearts, changing from wild to domestic over several thousand years.
Despite their transformation, cats still have three paws firmly planted in the wild. The dog's mind has been radically altered from that of its wolf ancestor. Cats, on the other hand, still think like wild hunters.
Cats are not humankind's creation. In contrast to almost every other domestic animal, cats retain remarkable control over their own lives. Most go where they please when they please and, crucially, choose their own mates. Unlike dogs, only a small minority of cats has ever been intentionally bred by people. No one has bred cats to guard houses, herd livestock or assist hunters. Their domestication was therefore driven largely by natural selection. Cats co-evolved with humans, moulding themselves into niches that we unintentionally provided.
For these reasons, cats cannot be considered completely domesticated, and much of their behaviour still reflects their wild instincts. To understand why cats behave as they do – especially in their relationships with us – we must understand these instincts.
Cats can be very affectionate, but they are choosy about the objects of their affection. This stems from their evolutionary past: wildcats are largely solitary and regard most other cats as rivals. Domestic cats' default position on other cats remains one of suspicion, even fear.
Domestication, however, has blunted some of their wariness. The demands of domestication – first the need to live cheek-by-jowl with other cats and then the forming of bonds with people – have extended cats' social repertoires beyond all recognition.
Social behaviour probably started to evolve as soon as cats began to congregate around granaries. Any cat that maintained its antagonism towards other cats would have put itself at a disadvantage when exploiting this resource.
Even today, wherever there is a regular source of food, a colony of feral cats will spring up – assuming local people allow it. Colonies can build up until several hundred cats are all living in close proximity to one another.
Clawful mess
In these colonies, society is based on cooperation between genetically related females. Mothers often drive away their male offspring after a few months to avoid inbreeding, leaving them to lead solitary lives. Where colonies consist of more than one family, they compete with one another. Colonies are therefore far from well-regulated. Cats seem to be incapable of sustaining a large number of friendly relationships, or of forming alliances between family groups in the way that primates do; negotiation skills this sophisticated lie beyond their capabilities.
Nonetheless, the switch to social living required a quantum leap in communication. For an animal as well-armoured as a cat, a tiff might escalate into a dangerous fight unless a system of signalling evolves that allows cats to assess others' moods and intentions. And this is precisely what happened.
For domestic cats, my research has shown that the key signal is the straight-up tail. In colonies, when two cats are working out whether to approach each other, one usually raises its tail; if the other is happy to approach, it raises its tail too. The tail-up signal almost certainly evolved during domestication, arising from a posture wildcat kittens use when greeting their mothers. Adult wildcats do not raise their tails to each other.
Once an exchange of tail-ups has been established, one of two things occurs. Either the cats rub heads, flanks and sometimes still-raised tails before separating, or they engage in mutual grooming, which has profound social significance in many animals. Both rubbing and grooming probably perform the same function for cats: cementing an amicable relationship.
The most important social skill a cat must learn in order to become a pet is, of course, how to interact with people. This must have its origins in interactions between cats – it has no other plausible evolutionary source.
Cats are not born attached to people. They are merely born with an inclination to trust people during a brief period when they are tiny.
Studies of dogs in the 1950s established the notion of a "primary socialisation period", when puppies are especially sensitive to learning how to interact with people. For dogs, this is between 7 and 14 weeks of age.
The concept also applies to cats, but starts earlier. A kitten that is handled regularly between 4 and 8 weeks generally develops a powerful attraction to people. One that does not meet a human until 10 weeks or later is likely to fear people for the rest of its life.
Cats do not suddenly stop learning about people when they pass the eight-week watershed. We know that they learn a great deal more about how to interact with people throughout the first year of their life.
Cynics often suggest that cats trick us into giving them food and shelter through faux displays of affection, and that owners project their own emotions onto their pets. But we feel such affection for cats with good reason. The human-like quality of their facial features is a factor, but it cannot be sufficient. Cats owe their success as pets to the fact that they have evolved an ability to interact with us in a way that we find appealing.
Even at the earliest stage of domestication, cats needed humans to protect and feed them when mice were in short supply. The cats that thrived were those that were able to reward people with their company.
Many people feel affection for cats, but what do cats feel for us? We know that they have the capacity to feel affection for other cats, and so it is probable that their attachment to their people is an emotional one.
Proving it is difficult, however, as we can only really judge cats' emotions by their actions – and cats do not wear their hearts on their paws.
Most owners would say that their cat displays contentment by purring. But purring is not at all straightforward. It clearly does occur when a cat is contented, and this may be the norm. However, a purring cat may be hungry, or mildly anxious. Some continue to purr even when their body language indicates they are angry. Occasionally, cats have also been heard purring when they were in distress or even during the moments before death.
Purring, then, does not necessarily reveal a cat's emotional state. Instead, it seems to be what behavioural ecologists refer to as a "manipulative" signal, conveying the general request: "please settle down next to me".
However, other signals, ones we tend to overlook, may be more genuine displays of affection. Relationships between adult cats seem to be sustained mainly through mutual licking and rubbing, so we should examine whether these also reveal affection directed towards us.
Many cats lick their owners regularly, but scientists have not yet investigated why this should be. The most likely explanation is that the cat is trying to convey something to its owner about their relationship. The reason must be basically affectionate, because two cats that do not like each other never groom each other. But until we know more about why cats groom one another, we can only speculate on why they groom us.
Cat owners also engage in a tactile ritual with their pets when they stroke them. Most owners stroke their cats simply because it gives them pleasure, and because the cat also seems to enjoy it, but stroking may also have symbolic meaning for the cat. Most prefer to be stroked on their heads, the area towards which cats direct their grooming.
Many cats do not simply accept stroking passively – they invite people to stroke them by jumping on their laps or rolling over. They also indicate where they wish to be stroked by offering that part of their body or shifting position. By accepting stroking, cats are engaging in a social ritual that is reinforcing the bond with their owner.
While touch is very important, the upright tail is probably the clearest way cats show their affection for us. A cat approaching its owner with a raised tail will often rub on its owner's legs. The form that the rub takes seems to vary from cat to cat: some rub just with the side of their head, others rub down their flank, some make contact with their tail. Many walk past without making any contact or perform their rubs on an object nearby.
Sometimes when this happens it looks as though the cat is scent-marking. But if scent is transferred, it does not seem to hold any particular significance for the cat. They seem to have learned that we are oblivious to the delicate odours that they leave on our legs. Cats presumably find rubbing against us rewarding in its own right – if they didn't, they would probably stop.
The sound of mewsic
Because many cats rub most intensely when they are about to be fed, they have been accused of showing nothing more than cupboard love. However, few cats confine their rubbing to mealtimes, and when two cats rub they exchange no additional reward. So an exchange of rubs is a declaration of affection – nothing more, nothing less.
Another way cats communicate with us is to attract our attention, usually by meowing. The meow is part of the cat's natural repertoire, but they rarely use it to communicate with other cats, and feral cats are generally rather silent. While all cats are apparently born knowing how to meow, each has to learn how to use this to communicate most effectively.
Once cats have learned that their owners respond to meows, many develop a range of sounds that, by trial and error, they learn are effective in specific circumstances. In this way, each cat and its owner gradually develop an individual "language" that they both understand, but that is not shared by other cats or owners.
So cats demonstrate great flexibility in how they communicate with us, which rather contradicts their reputation for aloofness. We could consider some of this behaviour manipulative, but only to the extent that two friends negotiate the details of their relationship. The underlying emotion on both sides is undoubtedly affection.
Nonetheless, we should not kid ourselves that a cat's relationship with people is its sole raison d'être. They form even stronger attachments to the place where they live. Well-fed, neutered cats should not feel the need for a territory of their own. Nevertheless, most still regularly patrol a small area around their home and are prepared to fight other cats to maintain control of it. What motivates them to pursue what seems to be an unnecessary remnant of their ancestral behaviour?
The answer is quite simple. Today's pet cats have only evolved their behaviour during the past 10,000 years, from a time when every cat would have had to hunt and therefore defend an area in which it had access to prey.
The importance of territory is emphasised by the fact that many pet cats stray and get "lost", even though they are well looked after. We see a clue from the significant proportion of owners – as many as a quarter in some areas – who, when asked where they obtained their cat, reply, "it just turned up one day". These cats were not feral: they were other people's pets, desperate for territory.
How can we use this new understanding of cats to improve their lives? Perhaps the most important lesson is that they retain much of their wild nature – especially with respect to other cats. Many spend their lives trying to avoid contact with other cats. All the while, their owners compel them to live close to other cats that they have no reason to trust, whether neighbours' cats, or a second cat. They find it increasingly difficult to avoid contact with others, so while cats may be the most popular pet in the world, I'm afraid that their very popularity is increasingly causing them to struggle.
A Cat Cafe (You Stroke Them, You Don't Eat Them)
The country’s biggest celebrities would aspire to no less for any event — a waiting list of 6,000 with the majority of them women. For this particular launch, though, the stars of the show are cats.
“If you want to meet the ladies, our café is going to be the place to go,” said Lauren Pears, founder of one of Britain’s first “cat cafés”, which is due to open after planning permission was secured this week.
So popular is the Japanese trend of cat-petting as a form of relaxation for non-pet owners that Lady Dinah’s Cat Emporium, in Shoreditch, East London, secured £109,000 from the public in an online “crowdfunding” campaign and has taken thousands of bookings. And that is even before it has any cats.
A “Pop in for a pat” voucher has become the most popular ticket in town: 253 were bought, allowing tea-drinking customers to stroke, play with and feed cats for two hours for just £5. More than 100 people signed up for a “Nine lives” card, allowing nine visits, 20 people paid £500 to sponsor a cat for a year and one generous person donated £20,000 to become the proud owner of one moggy.
Ms Pears has already planned speed-dating events geared towards getting men in too.
One hurdle was that several of the biggest animal charities in the country have been fighting to stop Lady Dinah’s Cat Emporium for the past three months. They claimed that the concept was inhumane and refused to give Ms Pears the cats she needed. “My business wouldn’t survive if my cats were not looked after,” she said.
The public are collecting strays from the streets of London and using social media sites to offer them to the café.
Lady Dinah’s Cat Emporium was inspired by Tokyo’s cat cafés, a phenomenon that began in 2009 and offered customers a chance to order a coffee and stroke one of several resident cats.
Ms Pears, 30, an Australian, started her career in the video-game industry in Brisbane. Visiting Tokyo in 2009, she went to a cat café and saw room for improvement.
“I thought it was a lovely idea but there were flaws,” she said. “The cats seemed tense. There was nowhere for them to hide. You didn’t actually want to touch them because they looked like they’d been prodded and poked all day. It was quite uncomfortable.”
She moved to England and initially forgot about it. Without any pets of her own, she hatched a plan last year with her friend Anna Kogan. They had always been in rented accommodation with a “no pets” policy and thought lots of other city-dwellers were probably in the same situation.
What if you could go cat-cuddling for an hour a day, she thought, and not worry about the demands of working life and hysterical landlords?Ms Pears is imagining a “cat café experience beyond compare”. Ten kittens will make Lady Dinah’s litter and she is looking for cats with complementary personalities. The venue can sit up to 50 guests at a time. While customers nibble sugar mice and cat-shaped cupcakes, the cats are free to prowl and pounce across their own human-free garden and climb indoor trees.
It is advisable to book a table before the cats get all the cream tea.
Rhino Horns
South African conservationists are lacing the horns of rhinos with poison in an attempt to put off poachers, who have killed more than 800 in the country this year.
Amid growing alarm at the growing danger to elephants and rhinos, the government’s agency for wildlife preservation in Kwazulu-Natal has turned what until recently was regarded as a vigilante method into a government-endorsed procedure.
In a pilot project, Ezemvelo KZN Wildlife, a state-run agency, has authorised holes to be drilled into rhinos’ horns. They are then infused with a mixture of indelible ink and insecticide, rendering the world’s most expensive commodity valueless and noxious — although not fatal — to the consumer.
It is illegal in South Africa to administer poison knowing there is a chance someone will take it. However, as rhino horn consumers are mainly from Vietnam, conservationists are gambling that the vets who inject the horn are unlikely to face complex extradition requests.
Rhino horn is widely sought after in Asia because it is considered to be an aphrodisiac and cure for a variety of diseases.
Last week a parliamentary committee in Kenya proposed a sentence of life in prison for anyone found to have been poaching the country’s most endangered animals. Parliament is expected to approve the measures this week.
The process of tipping the horns with poison was invented by Charles van Niekirk and Lorinda Hern. Their company, the Rhino Rescue Project, has infused 230 rhino horns on private game reserves since 2010.
“It is a great sign that our government does indeed take this problem seriously, contrary to what the public tends to believe,” Dr Hern said.
The project will last three years and, if successful, could be rolled out to all of South Africa’s 20,000 rhinos.
The indelible pink ink used to stain the horn will be visible to a poacher when he chops it off, and is designed to show up on an airport scanner.
It will be impossible to tell from the outside whether the horn has been infused with poison.
US Dog Industry
Alex Stone and his wife, Marissa McDaniel, both work full time. They have two dogs that they miss during the day, and often have trouble getting home to feed them. “Pets are like children and need to be on a schedule,” Mr. Stone said.
He was inspired to invent an automated feeder called the Feed and Go, an oval dish with a lid containing six rotating trays for wet and dry food, treats and medication. It can be controlled remotely by smartphone, tablet or computer.
Dog and cat owners can set six different, one-time feedings and 16 repeating feed times. They can also record a message to play at specific times throughout the day and even check in to see if their pets are eating — the dish has a webcam that connects to a wireless network.
Mr. Stone began taking preorders for the feeder in October. It costs $199 upfront or $20 a month for 12 months; the company, based in Los Angeles, has about 5,500 orders and plans to start shipping this spring.
Lisa Lavin, chief executive of Anser Innovation, getting in touch with her poodle, Hattie, through PetChatz. Credit Jenn Ackerman for The New York Times
Perhaps more important, many pet owners are treating their dogs and cats as if they were children — quite a shift from the days when the dog slept in the garage, ate table scraps and “occasionally got their burrs taken out,” said Clay Mathile, who built the pet food company Iams and sold it to Procter & Gamble for $2.3 billion in 1999.
That changed mind-set is driving billions in spending — $55.8 billion last year, according to the American Pet Products Association — and has encouraged a wave of innovation, with many products and services incorporating sophisticated technologies.
Laird Koldyke is founder and managing director of Winona Capital Management in Chicago, which has invested in PetSense, a Scottsdale, Ariz., chain with nearly 100 stores in the United States. He said the change in consumer behavior was most apparent among young professionals, who are waiting longer to marry and have children, and empty-nesters, whose children have grown and left.
“There’s this desire to share something together, and that’s often a pet,” Mr. Koldyke said.
Combine that desire with rising education and income levels, he said, and you have people migrating toward higher-end products.
Some other examples:
PetChatz enables pet owners to interact with their dogs or cats when they cannot be with them. The device can be flush-mounted over a power outlet and has a speaker, webcam, LCD screen, and scent and treat dispensers, as well as sound and motion sensors.
Through an app on a phone, tablet or computer, pet owners can use PetChatz to summon their pets, see them, talk to them and dispense a treat and a scent, said Lisa Lavin, a co-founder and chief executive of Anser Innovation in Minneapolis. “It’s like multisensory Skyping,” she said. Dogs quickly learn they need only walk or bark near PetChatz to “call” their owners, who are alerted through the app to the motion or sound.
PetChatz is the first product from Anser Innovation and should be available this spring. Ms. Lavin said the company had raised about $2.5 million from angel investors. The product will retail for $349.
DogTV is a 24-hour television channel with content geared to dogs, especially those left alone during the day. Founded in 2012 by Gilad Neumann, an Israeli entrepreneur, the company had more than $5 million in revenue last year and moved from suburban Tel Aviv to Sunnyvale, Calif. The station was introduced nationwide last August on DirectTV as a premium subscription channel that costs $5 a month. Dogs on the go can watch, too, with DogTV Anywhere, the company’s new multiplatform, live-streaming app.
The content includes “psychoacoustic classical music” — a cross between classical and elevator music that keeps dogs calm — and images of animals, especially other dogs, that the dogs find stimulating. The programming also includes images and noises that can be stressful to dogs, like children and ringing doorbells.
“Exposing dogs gradually gets them used to those situations so they behave better in the real world,” Mr. Neumann said.
Another company that helps dogs endure those lonely hours is iFetch, which lets small and medium-size dogs play fetch by themselves. The iFetch is a motorized toy with a funnel on top, where the dog can insert a ball, and a nose at the front, from which the ball is ejected. Depending on the setting, the ball can travel 10, 20 or 30 feet in the air, said Denny Hamill, who founded the company iFetch in Austin, Tex., with his daughter, Debbie Hamill.
They introduced the product in December, financing it with a significant personal investment and a Kickstarter campaign that raised almost $90,000. The company has 2,500 orders for the $100 device. “If you set the machine at 30 feet, that’s a good, hard game of fetch for a dog,” Mr. Hamill said.
DogVacay, an Airbnb for dogs, was founded in March 2012 by Aaron Hirschhorn and his wife, Karine Nissim Hirschhorn, after they left their two dogs in a kennel while on a 10-day trip to the East Coast. The Hirschhorns, who live in Venice, Calif., were shocked at the bill: $1,400. “It was more than our whole vacation,” Mr. Hirschhorn said. “And one of our dogs, Rocky, was hiding under a desk for two days after the trip.”
Before listing on the site, hosts go through a five-step vetting process; the company said it accepted only 30 percent of those who applied. During the dog’s stay, the owner gets regular photo and video updates through DogVacay’s mobile app. The average price is $28 a night, less than half what a typical kennel charges, Mr. Hirschhorn said. DogVacay takes a 15 percent cut of the host’s fee and provides insurance for both host and customer, along with round-the-clock support. The site has more than 10,000 host families in the United States and Canada and has raised $22 million in investment capital.
JustFoodForDogs, a Newport Beach, Calif. company founded in April 2010, sells nutritionally balanced, human-grade food prepared in state-of-the-art, Agriculture Department-certified kitchens. “Our food is more digestible and easier for a dog’s body to convert to energy,” said Shawn Buckley, the company’s founder. The food is delivered fresh in Los Angeles and Orange Counties and is shipped frozen — packed in dry ice — elsewhere in the continental United States.
Mr. Buckley was prompted to enter the dog food business after learning what ingredients — including dehydrated poultry feces — were in the food he had been feeding his dogs. JustFoodForDogs costs about $30 more a month than a premium kibble dog food, but the company also has do-it-yourself kits that cost $18 and include a recipe, packets of human-grade nutrients and an instruction video for making about 30 pounds of food, Mr. Buckley said.
Since late 2011, the company has made no less than 9,000 pounds of food a week, and it now has commercial kitchens in Newport Beach, West Hollywood and Santa Monica.
Mr. Buckley said JustFoodForDogs, which has raised about $2.6 million in investment capital, was already profitable. And he said he was confident that changes in the pet industry were just beginning: “Within my lifetime there will come a day when people look back and say: ‘Remember when all dog food came in bags? Remember that we kept meat in a bag for three years?’ ”
How far Can You Drop A Cat?
(New Scientist Last Word Q)
A friend of mine reckons that you can drop a cat from any height and it will survive unhurt because its terminal velocity is lower than the speed at which it can land unhurt. Can someone confirm or refute this because kittens in my house now look strangely at my friend. I’m sure this can’t be true, can it?
Anna Goodman, Oxford, UK
I’m reminded of a study reported in the Journal of the American Veterinary Medicine Association in 1987 by W. O. Whitney and C. J. Mehlhaff, two New York vets, entitled “High-rise syndrome in cats”. The study was also summarised in Nature a year later.
Briefly, the authors examined injuries and mortality rates in cats that had been brought to their hospital following falls ranging from between 2 and 32 storeys. Overall mortality rates were low, with 90 per cent of the cats surviving, a fact that supports the correspondent’s ailurophobic friend. However, the study unexpectedly found that the incidence of injuries and death peaked for falls of around seven storeys, and then actually decreased for falls from greater heights.
The Nature article presents three main variables that determine injury and mortality rate the speed reached by the moggy, the distance in which said moggy is brought to a stop, and the area of moggy over which the stopping force is spread. While concrete streets work in nobody’s favour when it comes to stopping falling items, cats suffer relatively little injury (compared to their owners) because they do indeed reach lower terminal velocities and absorb the shock of stopping so much better. A falling cat has a higher surface area to mass ratio than a falling human, and so reaches a terminal velocity of about 100 kilometres per hour (about half that of humans). They are also able to twist themselves so that the impact is spread over four feet, rather than our two. And as they are more flexible than humans, they can land with flexed limbs and dissipate the impact forces through soft tissue.
To answer the paradoxical increase in survival rates once seven storeys has been reached, the authors suggested that an accelerating cat tends to stiffen up, reducing its ability to absorb the impact. However, once terminal velocity is reached, there is no longer any net force acting on the cat, and so it will relax, increasing both its flexibility and the cross-sectional area over which the impact is dissipated once the cat hits the ground.
I’d still keep your friend away from your kittens, if I were you. Few buildings in your home town of Oxford are seven storeys high, but there are plenty of rivers about.
Animals Self-Medicating
When we fall ill we visit a clinic or a pharmacy. Our ancestors, however, didn’t have that luxury. Instead, early humans likely observed and learned from sick animals that healed themselves by eating certain plants. Yet, only in the past two decades have biologists and chemists begun to recognize that animals do self-medicate – select and use substances specifically to cure themselves of parasites and ailments.
Early accounts of animal self-medication came in the late 1980s from Michael Huffman, a primatologist at Kyoto University. His decades-long research on chimpanzees, which revealed that they use plant compounds to rid themselves of parasites, helped established self-medication as a fundamental animal behavior.
“Any animal species alive today is alive in part because of its ability to adapt and to fight off diseases,” Huffman says. Self-medication does not require high intelligence, but was simply the reaction of animals to remove an ailing symptom that evolved into strategies to expel parasites. “Self-medication is a very basic behavior that’s important to the survival of so many species,” he says.
And animal self-medication points to a treasure larger than mere fascination. By following the animals’ lead, we tap into a medicine vault furnished by millions of years of natural selection. The world’s best bio-prospectors – the animals themselves – may very well show us new pharmaceuticals to improve the health of our livestock and ourselves.
In 1987, Huffman was observing chimpanzees in Mahale Mountain National Park, Tanzania, when he noticed a sick chimpanzee acting strangely. That chimpanzee peeled the bark off branches of a small tree, chewed the pith within and sucked out the juices.
The tree was Vernonia amygdalina, a poisonous plant known in English as bitter leaf and sometimes locally referred to as ‘kill goats.’ “It’s not something you want to play with,” Huffman warns.
Why was the sick chimp chewing on the bitter pith of this poisonous plant? Huffman and his colleagues showed that chimpanzees that chewed the pith often had higher parasite loads than other chimpanzees. They also found that compounds from bitter pith strongly suppress the parasitic nematode Oesophagostomum stephanostomum, a gastrointestinal parasite that can be deadly to chimpanzees. Huffman found 88 percent fewer of the nematode’s eggs in the feces of a wild chimpanzee about twenty hours after the chimp chewed bitter pith.
Inspired by this discovery, new bioactive compounds were subsequently identified in the bitter pith of V. amygdalina, many of which suppress amoeba, tumors and bacteria.
African tribes have long used the plant to remove intestinal parasites and treat disease – and now researchers are realizing its benefits too. Clinical trials in recent years have found that V. amygdalina can prevent cancer and may help treat malaria.
The Chinese lesser civet eats everything from insects and small animals to fruits and eggs. Still, scientists led by Hsiu-Hui Su (National Pingtung University of Science and Technology, Taiwan) were puzzled when they examined the feces of wild civets and found bundles of intact leaves, folded and stacked into tens of layers. The civets apparently swallowed the leaves without chewing.
Prying open the leaf bundles, the scientists found hints that could explain leaf-swallowing by civets: live, parasitic adult worms were caught in the folds of the leaves.
Gastrointestinal nematodes are likely a common pain among animal species. In response, various animals have evolved similar tactics to rid themselves of the worms. One such tactic is to swallow leaves whole and let the leaf masses sweep through the gastrointestinal tract, catching some of the parasitic worms along the way and expelling them with the feces.
Great apes (including the chimpanzees observed by Huffman in Africa) swallow leaves, as do snow geese, brown bears and gibbons. The animals use plants specific to their habitats, but they always select rough, hairy leaves which might better trap the worms.
Grazing animals practice admirable sanitation. For example, horses grazing in a crowded pasture establish a ‘toilet’ – an area restricted for defecation. Such sanitation helps these animals as they easily pick up parasites with every mouth of fresh grass.
Some grazing animals, however, have taken to medicating themselves with tannins (a familiar flavor component of red wine) when they are parasitized by gastrointestinal nematodes. For example, parasitized goat kids of the Mamber breed in the Middle East have been observed eating more of the tannin-rich shrub Pistacia lentiscus, a plant the goats normally shun. Feeding on P. lentiscus reduces the nematode egg counts in the goats’ feces to negligible levels.
In a separate experiment, lambs infected with gastrointestinal nematodes tasted and ate more of a tannin-supplement that scientists provided. The supplement offered very little nutrition, but the lambs that ingested the tannins successfully relieved their infection levels. After three weeks, when infection levels had subsided, the lambs’ preference for tannins also stopped.
Such self-medication could prove helpful for farmers. Scientists are now studying the possibility of providing livestock with medicinal foliage to allow them to medicate as and when needed – which could reduce farmers’ reliance on deworming drugs.
Most parents wouldn’t feed their babies foods laced with alcohol, but fruit fly Drosophila melanogaster mothers have no qualms – especially if it protects their babies from parasites.
Parasitic wasps hunt for Drosophila maggots, eager to plant their eggs into the maggot. The maggots however, can beat the parasitoids with a little alcohol. Parasitized maggots on a 6%-alcohol diet have been shown to survive much better than those on non-alcoholic diets. In the wild, maggots that are parasitized seek out rotting fruits with higher alcohol levels.
And what’s more, mother fruit flies can anticipate infection and medicate her babies in advance. Studies have found that when wasps are around, flies prefer to lay their eggs in a substrate enriched with 9-15% alcohol; otherwise, the mother opts for 3% alcohol. A competent mother fruit fly, it seems, knows when to provide her children with an alcoholic childhood.
Todd Schlenke, visiting assistant professor at Reed College, Oregon, suspects we will discover more animals using alcohol as medicine. “You can find lots of smaller organisms (like insects) in rotting fruit, and lots of larger organisms (like mammals) that consume rotting fruit,” he says. “So it would be surprising if fruit flies were the only ones using it as part of a defense mechanism.”
How pets got their spots (and floppy ears)
CHARLES DARWIN was fascinated by the many breeds of domesticated birds and mammals. His cataloguing of the unusual and sometimes bizarre varieties of pigeon was more than a hobby: he was an avid pigeon breeder, and devoted many pages of On The Origin of Species to documenting how readily the birds change their form when selected for unusual traits such as webbed or feathered feet.
The study of domesticated animals was a key pillar in Darwin's argument for natural selection. The changes he observed in pets and farm animals showed that artificial selection by humans – whether for webbed feet in pigeons or more milk in dairy cows – can quickly produce heritable changes from the "wild type" state. This provided a compelling argument that analogous "natural selection" by Mother Nature could produce similar changes and eventually lead to new species.
Darwin didn't limit himself to pigeons. Through correspondence with hundreds of breeders, he compiled information about virtually every domesticated species of the time, from chickens and ducks to dogs, cats, pigs, cows and horses. He published his research in 1868 in the massive two-volume Variation in Animals and Plants Under Domestication, which even today remains the most comprehensive work on the subject.
Darwin's detailed research uncovered a remarkable regularity, which has recently been dubbed the domestication syndrome. In all domesticated mammalsMovie Camera, a bizarre collection of traits shows up time and again. Besides a general docility, Darwin noticed that coloration is modified (for example, black and white coats appear), teeth and brains get smaller, and snouts shorter. In many species, the tail may become curly or reduced, or ears flop over. Why should this unusual set of features appear together in different species that were domesticated at different places and times? Although Darwin speculated that some traits might have been specifically selected for (black-and-white coloration, for instance, might make lost livestock easier to find), he never came up with a convincing solution for the whole set of traits.
Recently, together with biologists Adam Wilkins and Richard Wrangham, I proposed a novel solution to Darwin's mystery (Genetics, vol 197, p 795). Our hypothesis hinges on the fact that virtually all of the traits involved in the domestication syndrome are derived from the same source: an unusual type of cell called the neural crest.
Neural crest cells arise during early embryonic development, when the brain and spinal cord are forming. These cells originate on the embryo's back and migrate to form the adrenal glands and parts of the nervous system, along with pigmentation cells and major portions of the skull, teeth and ears.
Our hypothesis suggests that selection in any newly domesticated species is focused on tameness. Animals that become fearful and agitated when encountering humans are unlikely to breed in captivity. Fearful animals are also more likely to bite, kick or otherwise injure their human caretakers. Thus docility and a lack of fearfulness are among the most important traits to appear when a wild species is first domesticated.
How does tameness arise, physiologically? A key change is that the adrenal glands and sympathetic nervous system, which are jointly responsible for the "fight-or-flight" response to scary events, mature late. When young animals are first exposed to their human custodians, they do not have a full-blown physiological capacity to feel afraid. Thus they remain relatively calm during these encounters, and by the time their fear response matures they have already been habituated to humans. This is precisely what it means to be "tame".
Wolves, for example, have a brief window of time after their eyes and ears start working before they are capable of mounting a mature fight-or-flight response. Anyone wishing to tame a wolf must expose it repeatedly to humans during this period, which lasts until the age of about 1½ months. In contrast, many experiments have shown that this "socialisation window" lasts until the age of 4 to 10 months in dogs, depending on the breed, after which time dogs exposed to people for the first time will remain fearful regardless of how much they interact with humans.
Now comes the interesting part. We hypothesise that the late maturation and general under-functioning of the adrenal glands and sympathetic nervous system – leading to docility – derives from reduced numbers and delayed migration of neural crest cells in the embryo. Because the cells are the precursors of teeth, pigmented skin, snouts, ears etc, these are also smaller or develop late. Rather than humans selecting for black-and-white coloration, we suggest that pigmentation changes and other traits of the domestication syndrome are just unintended side effects of selection for tameness.
Strong evidence in favour of our hypothesis comes from experimental studies of domestication. The most famous were carried out with foxes in Siberia over many decades, beginning in the late 1950s. The researchers attempted to create a new domesticated species by selecting only for tameness. They started with unselected, fearful foxes, and carefully tested their young for fearfulness and friendliness. Only the friendliest offspring were chosen to breed.
After a surprisingly short time – less than 10 generations – the Siberian team bred a strain of foxes that is amazingly tame and unafraid of humans (see photo above). What's more, these foxes showed most of the other traits of the domestication syndrome, such as reduced and delayed adrenal function and a longer socialisation window (as required by our hypothesis), plus pigmentation changes, floppy ears and shortened snouts. These experiments have been repeated in rats and mink, with similar results.
Tameness is the only attribute selected for in this work. Nonetheless, the traits of the domestication syndrome pop up much more frequently than expected if they were random.
There is other evidence. We predicted that neural crest development changes should be pervasive in domesticated species compared to wild counterparts. A study published just last month confirms this for multiple neural crest genes in domesticated cats (PNAS, vol 111, p 17230).
Our hypothesis leaves several questions open. The most obvious concerns the brain: the neural crest cells make no direct contribution to the central nervous system, so it is unclear whether cognitive changes in domesticated species can be fully explained by the same mechanism, or whether interactions between the neural crest and the developing brain are important in brain reduction as well.
Further research is needed, but our hypothesis is consistent with available data. We think it finally provides a coherent explanation for the characteristics of domestication that have puzzled biologists since Darwin.
Owl Cafe
It is getting dark and three security guards are covertly guarding the entrance to a deserted-looking shop.
Black curtains have been drawn secretively across the front windows and the door staff greet guests with only the faintest of nods as they climb out of taxis and slink towards them.
This is not the entrance to an A-list after-party nor the door to a seedy strip club, but the newest, most hipster night out.
The bouncers are guarding the doors of the first owl café, in east London. Inside, a parliament of owls is waiting to meet the lucky few who managed to get a ticket.
Without the security and the hidden location it is likely that the 99,000 people who missed out in a ballot for places would flood the venue.
When it was first announced that the capital would be getting its first pop-up owl café, a phenomenon that started in Tokyo, more than 100,000 people applied for one of the £20 tickets.
The trendiest part of town is the perfect location for Annie The Owl. The café serves only smoothies made of ingredients such as kale in glass milk bottles and the venue is, of course, nocturnal, which suits the night-loving hipsters living in nearby Shoreditch. The 750 fortunate people who got tickets received the address via an email just hours before the event, and were asked to be inconspicuous when they turned up as well as keeping the destination “private and confidential”.
The café is having two sittings for each one of its five-night run: 7pm to 9pm and 10pm to midnight, which accommodate 75 people.
During the evening, Charles Mason, the head falconer, introduces a white-faced scops owl called Moy, and Sheba, a European barn owl to a delighted, cooing crowd.
After a short talk about each bird, the owls are walked around the room by the falconers who fit a huge glove on to guests’ left hands if they want to hold one.
Those wearing cool, oversized glasses are advised to take them off because “owls hate glasses”. Moy and Sheba claw on to the glove and swivel their heads alertly.
Then Archimedes, a tiny female burrowing owl and Taj, a huge Bengal eagle owl are brought out. Taj is so big and impressive he almost hypnotises the crowd.
Mr Mason, who owns the birds and runs Animal Encounters, an animal party company, said the number of people who wanted to attend was “amazing”.
He believed the Harry Potter books and films had sparked the public’s interest in the birds.
“It’s hopefully introducing people to nature. People in cities are coming at the event from a different viewpoint but by the end they go away thinking that they’re really beautiful animals,” he added.
“Holding them and seeing them close up you can feel their different weights and see the different colourations of their feathers.
“It’s the eyes that make people so fascinated, it’s an anthropomorphic feeling. Owls are a pretty special thing. I couldn’t live without them.”
Dogs and oxytocin
Have you ever gazed deep into your dog’s loving eyes and thought: “You devious little parasite”? Your cynicism may not be unwarranted. Dogs may have hijacked the bonding mechanism between parents and babies by hitching a ride on the body’s “cuddle” hormone.
“Dogs are more skilful than wolves and chimpanzees, the closest respective relatives of dogs and humans, at using human social communicative behaviours,” a team of Japanese biologists wrote in Science. “More specifically, dogs are able to use mutual gaze as a communication tool.”
The researchers believe this could stem from dogs “co-opting” the way that staring into the eyes of their loved ones raises humans’ levels of oxytocin, the bonding hormone. It does not appear to hurt the dogs’ prospects that some of their facial expressions resemble those of human infants. “These alterations may be related to paedomorphic characteristics in dogs, which enabled them to retain a degree of social flexibility and tolerance similar to that of humans,” the scientists wrote.
To test the theory that dogs benefit from a “feedback loop” of oxytocin where looking their owners in the eye fills both parties with a warm bouquet of bonding chemicals, the biologists observed how dogs and wolves behaved when they were left in a room for half an hour with the humans who looked after them. While the wolves were mostly indifferent to their “owners” and showed little change in their oxytocin levels, the amount of oxytocin in the dogs’ urine shot up when their owners stroked them or looked into their eyes. Similar chemical changes were seen in the humans.
Dog Poo
Dog owners are more likely to clean up after their animals in the afternoon than the mornings, pretend not to notice what their canine chum has done if they don’t want to pick it up, and construct dirty protests against a society that oppresses their dog’s right to defecate at will.
This is the conclusion of a study by an academic who has spent the past decade following wayward dog walkers.
Like many people, Matthias Gross is not a fan of dog poo. Indeed, he finds society’s tolerance of it inexplicable. “Whereas the presence of human faeces on the street is widely considered in the West as a throwback to medieval times, the depositing of faecal matter by dogs appears to be accepted as normal.”
Gross is a professor of sociology at the Helmholtz Centre for Environmental Research in Leipzig, Germany. In 2003, he decided to apply his talents to an ethnographic study of dog owners. Leaving the house 15 minutes earlier than necessary, to allow time, he would covertly record the movements (in more ways than one) of dogs on his way to work, then write them up on the train.
The result, after several thousand hours of observation, is his magnum opus. “Natural waste: canine companions and the lure of inattentively pooping in public.” The study, published in the journal Environmental Sociology, has uncovered some unusual habits.
“In the afternoon, dog owners appeared much more attentive to excrement removal,” he wrote. He came to recognise the dog owners on his route, and found that “those that did not clean up in the morning did regularly clean up in the afternoon”.
He also began to notice patterns. “If the poop is not cleaned up, the owner will sometimes pretend that he or she has not seen the dog pooping – by talking earnestly into their phone or using an iPad.” In ethnographic studies this is called strategic nonknowledge. He added: “Right before the dog owner grabs for the poop with the bag, she or he takes a look over the shoulder, perhaps to make sure that he or she can be rendered a ‘good’ dog owner.”
Professor Gross’s paper also benefited from luck. It turned out that the decade of his field work was a tremendously exciting time — it saw the arrival of the cultural phenomenon known as the “poo tree”, in which used bags are hung on branches or railings or flung into bushes.
In all his hours of observation, he never once saw such a bag being placed. He believes the tree is a deliberate protest, made more powerful by anonymity. “Perhaps it is important to them to be seen to be doing what is expected of them while at the same time rejecting this social expectation and expressing their scorn towards those who demand it by parodying the act.”
Unfortunately he could not validate this theory. Dog owners declined to be interviewed. Approaches were often met with aggression, he said. “‘Mind your own business’ and ‘Don’t you have anything else to do?’ were among the more friendly statements.”
Acorn Woodpeckers
Wolves in Yellowstone
The reintroduction of wolves in Yellowstone National Park in 1995 is a conservation success story that has encouraged advocates of “rewilding” in Britain (Ben Webster writes).
The 70-year absence of wolves from the park, in Wyoming, allowed deer numbers to grow at an alarming rate because they had no natural predators — and they quickly destroyed young trees and other vegetation, leaving much of the land barren. After the wolves were reintroduced, the trees grew again and songbird numbers began to recover. Bald eagles arrived soon after to feed on deer carcasses left by wolves.
There have been claims that the wolves helped to change the course of rivers, with less erosion from newly forested banks meaning they meandered less.
The Lynx UK Trust believes that similar benefits could be felt in Britain. The Deer Initiative, a partnership of government agencies, conservation groups and landowners, supports the wild cats’ reintroduction.
There are more than 1.5 million deer in Britain.
Many sheep farmers fear that the arrival of a 60lb predator will threaten their flocks, though there have been few problems caused by such lynx reintroduction schemes in Germany and Switzerland. Individual lynxes kill two or three sheep a year on average.
Micro Pigs
Cutting-edge gene-editing techniques have produced an unexpected byproduct — tiny pigs that a leading Chinese genomics institute will soon sell as pets.
BGI in Shenzhen, the genomics institute that is famous for a series of high-profile breakthroughs in genomic sequencing, originally created the micropigs as models for human disease, by applying a gene-editing technique to a small breed of pig known as Bama. On September 23, at the Shenzhen International Biotech Leaders Summit in China, BGI revealed that it would start selling the pigs as pets. The animals weigh about 15 kilograms when mature, or about the same as a medium-sized dog.
At the summit, the institute quoted a price tag of 10,000 yuan (US$1,600) for the micropigs, but that was just to "help us better evaluate the market”, says Yong Li, technical director of BGI’s animal-science platform. In future, customers will be offered pigs with different coat colours and patterns, which BGI says it can also set through gene editing.
With gene editing taking biology by storm, the field's pioneers say that the application to pets was no big surprise. Some also caution against it. “It's questionable whether we should impact the life, health and well-being of other animal species on this planet light-heartedly,” says geneticist Jens Boch at the Martin Luther University of Halle-Wittenberg in Germany. Boch helped to develop the gene-editing technique used to create the pigs, which uses enzymes known as TALENs (transcription activator-like effector nucleases) to disable certain genes.
How to regulate the various applications of gene-editing is an open question that scientists are already discussing with agencies across the world. BGI agrees on the need to regulate gene editing in pets as well as in the medical research applications that make up the core of its micropig activities. Any profits from the sale of pets will be invested in this research. “We plan to take orders from customers now and see what the scale of the demand is,” says Li.
Animal models
Compared to rats or mice, pigs are closer to humans physiologically and genetically, making them potentially more useful as a model organism for human disease. However, their larger size means that they cost more to keep and require bigger drug doses when they are used to test a pricey experimental medicine.
Bama pigs, which weigh 35–50 kilograms (by contrast, many farm pigs weigh more than 100 kilograms), have previously been used in research.
To make the smaller, gene-edited micropigs, BGI made cloned pigs from cells taken from a Bama fetus. But before they started the cloning process, they used TALENs to disable one of two copies of the growth hormone receptor gene (GHR) in the fetal cells. Without the receptor, cells do not receive the ‘grow’ signal during development, resulting in stunted pigs.
Show stealers
BGI then created further micropigs by breeding stunted male clones with normal females. Only half of the resulting, naturally conceived offspring were micropigs, but the process is more efficient than repeating the full cloning procedure, and avoids potential health problems associated with cloning. Among the 20 second-generation gene-edited pigs, BGI has observed no adverse health effects, says Li.
He says that the micropigs have already proved useful in studies of stem cells and of gut microbiota, because the animals' smaller size makes it easier to replace the bacteria in their guts. They will also aid studies of Laron syndrome, a type of dwarfism caused by a mutation in the human GHR gene.
The decision to sell the pigs as pets surprised Lars Bolund, a medical geneticist at Aarhus University in Denmark who helped BGI to develop its pig gene-editing program, but he admits that they stole the show at the Shenzhen summit. “We had a bigger crowd than anyone,” he says. “People were attached to them. Everyone wanted to hold them.”
They could meet a preexisting demand. In the United States, for instance, reports have surfaced of people who wanted a porcine lap pet, but were disappointed when animals touted as 'teacup' pigs weighing only 5 kilograms grew into 50-kilogram animals. Genetically-edited micropigs stay reliably small, the BGI team says.
Pig problems
But gene editing will not solve other drawbacks of pet pigs, says Crystal Kim-Han, who runs a rescue operation for abandoned pigs near Las Vegas, Nevada. For instance, if the animals are locked up in an apartment with no place to root or dig, they can become destructive. She also expects micropigs to have additional medical problems, similar to pets created by selective breeding. “What happens down the road when these animals need care?” she asks.
Some researchers think that dogs or cats will be next up for genetic manipulation. Scientists and ethicists agree that gene-edited pets are not very different from conventional breeding — the result is just achieved more efficiently. But that doesn’t make the practice a good idea, says Jeantine Lunshof, a bioethicist at Harvard Medical School in Boston, Massachusetts, who describes both as “stretching physiological limits for the sole purpose of satisfying idiosyncratic aesthetic preferences of humans”.
Dana Carroll, a gene-editing pioneer at the University of Utah in Salt Lake City, adds: “I can certainly imagine resistance to manipulating dogs, even though all of the current breeds are the result of selective breeding by humans.”
Daniel Voytas, a geneticist at the University of Minnesota in Saint Paul, hopes that any buzz over gene-edited pets does not hamper progress in developing gene-editing techniques for alleviating human disease and creating new crop varieties. “I just hope we establish a regulatory framework — guidelines for the safe and ethical use of this technology — that allows the potential to be realized," he says. "I worry that pet mini pigs distract and add confusion to efforts to achieve this goal."
Beetle That Preys On Frogs
LET ME GET real about amphibians: The things are cocky. They’re so much bigger than their helpless prey - things like worms and insects - that they tend to indiscriminately snatch up anything that’s a manageable size.
But like the Mighty Ducks rose up to defeat the seemingly unbeatable Team Iceland, one beetle has evolved to put amphibians in their place. As larvae, beetles of the genus Epomis actually entice frogs and toads and salamanders to attack them, then whip around and sink their huge, hooked jaws into the attackers, slowly draining the life out of them. When the larvae transform into adult beetles, they get right back to it, only now they dispatch amphibians even more brutally. Like, a kind of brutality that involves snipping a frog’s leg muscles so it can’t escape.
Imagine, if you will, that you’re a toad. You’re hopping along when something catches your eye: a beetle larva shifting its jaws and antennae back and forth. Your brain tells you that anything that moves and that’s small enough for you to overpower is probably food.
So it’s decided. As you draw closer to your victim, its movements get more rapid. You draw closer still, and strike.
One of two things is going to happen at this point, neither of which will end—how should I say—well for you. You’ll get the larva in your mouth and it’ll sink its jaws into your tongue, or the larva will get you somewhere on your skin—your lips or throat or flank. The larva is just too fast for you, and may be so smooth that it can repel that famous tongue of yours.
The second outcome, though, is you manage to swallow it. Not that that will do you any good. Scientists once watched a toad nab and successfully swallow a Epomis larva, only to throw it up two hours later. At first the larva lay motionless, but then suddenly it snapped out of it and attacked the toad again.
So … you’re screwed. That larva ain’t about to let go. In fact, it starts digesting your tissue. But strangely, none of your blood is coming out, and indeed “when you slice a larva open you don’t see it full of red blood,” says Gil Wizen, an entomologist at the University of Toronto. What’s probably going on here, Wizen reckons, is the larva is secreting enzymes onto the toad to melt its flesh. “So you can say that the digestion is already beginning before the food enters the mouth,” he says.
Those double hooked jaws sink into amphibian flesh and don’t let go. How’s that for attachment issues. GIL WIZEN
All the while, you go about the life of a toad. You take a swim and gobble up insects. You will not, however, turn into a prince, because after two days, you’re so weakened you can no longer move. It’s at this point that the larva enters what Wizen calls “the predation stage.”
The larva begins chewing more, says Wizen, “and what we see is that it sort of tears tissues from the amphibian’s body. After a few hours the amphibian is reduced to just a pile of bones and just a little bit of skin.”
But this was no crime of passion. The larva is more like a serial killer. Over the course of its development, it can take down as many as nine toads, frogs, newts, or salamanders. It’s got such an appetite because it goes through three phases, known as instars, in which it needs ever more food. During the first instar, when it’s relatively small, it’ll take down just one victim. In the second instar, though, it’s two or three. In the last, as many as five.
And like a serial killer, its methods grow ever more complex as it matures. The adult beetle ups its game into some seriously sadistic stuff. While it isn’t as picky an eater as the larva, feeding on worms and other insects and even injured rodents and birds, it too loves it an amphibian.
The adult beetle doesn’t lure the victim like the larva, but instead goes full-tilt rodeo with it, jumping on a toad’s rear and sinking its jaws into the flesh. These jaws are different, though. “The jaws of the larva are hooked, modified to lock onto the amphibian’s skin,” says Wizen, “whereas with the [adults], they have serrated jaws.” The adult’s mouthparts aren’t modified to hold on tight, so it has to work fast.
The beetle has jumped onto the rear of the toad for a reason. Once the victim stops bucking, the beetle makes a small incision on the lower back. “We don’t think they damage the spine of the amphibian,” Wizen says. “But what we do think - we still need to confirm this - is that they cut the connecting muscles [of the legs] so the amphibian doesn’t have any way to escape.”
With the bronco incapacitated for good, the beetle can take its time gnawing on the victim alive. When it fills up, it trots off. If the toad isn’t yet dead, something like a bird or mammal will happily finish it off.
The whole weird circus defies belief—and bends the rules of nature. In only around 10 percent of cases is a predator smaller than its prey. Beyond that, the relationship between the Epomis beetle and its amphibian victims may in fact be unprecedented (as far as science knows). Wizen and his colleagues cite only one other case in which a prey becomes the predator: A scientist in the ’80s transferred rock lobsters, which eat snails known as whelks, to an environment with an abnormally large population of the prey, which flipped and became the predators. But that was human meddling. Epomis has evolved over millennia to turn amphibians - the eternal enemies of insects - into prey.
The relationship also resists definition. While Epomis is certainly predatory, it’s also in a way parasitic. As a larva, it doesn’t necessarily kill its victims, sometimes filling up enough and just dropping off (indeed, Wizen has collected toads with the tell-tale scars of an attack). And as I mentioned earlier, adults also don’t necessarily kill their victims either. So Epomis seems to be a kind of predator-parasite hybrid.
Raptors Starting Bush Fires
Birds of prey in Australia are suspected of starting fires to drive their prey from undergrowth. Black kites, along with brown falcons, are sufficiently intelligent to start fires intentionally, scientists have said.
At least two raptors, the black kite and the brown falcon, have been seen swooping on smoldering twigs and embers, and carrying them on to unburnt ground, scientists have been told, in what would be the first case of animals deliberately using fire. The birds swoop on small marsupials and large insects as they are flushed from the bush by the flames.
Bushmen, rangers and Aborigines have provided researchers with accounts of the birds starting fires in northern Australia. Scientists are preparing a paper on the phenomenon.
Bob Gosford, a Darwin lawyer, and Mark Bonta, a Penn State University scientist, have compiled a study suggesting that the birds could be a third force, besides man and lightning strikes, causing bush fires. At least 14 rangers interviewed by researchers, along with numerous Aborigines and several firefighters, have described the ability of birds to gather burning material and transport it to start new blazes.
“Reptiles, frogs and insects rush out from the fire, and there are birds that wait in front, right at the foot of the fire, waiting to catch them. Small fires often attract so many birds that there is insufficient fleeing prey for all, so a bird that was being beaten to its food might benefit from starting a new fire with less competition,” Mr Gosford told the IFL Science website.
Witnesses reported that the birds could carry smoldering sticks at least 50 metres (150ft) without the fire going out or singeing the bird, and possibly up to 500 metres, helping to explain how blazes have jumped fire breaks.
Steve Debus, from the University of New England, an expert in predatory birds, told The Times that he believed it would be difficult for researchers to distinguish between birds incidentally grasping burning twigs with prey and those deliberately picking them up.
“However, I think black kites and brown falcons are sufficiently intelligent to intentionally spread fires by dropping burning embers, because black kites have been seen to drop bread scraps from picnic areas into nearby waterholes to bait fish within striking range,” Dr Debus said.
Brown falcons and black kites can be found across most of Australia. Their fire-spreading behaviour has not been recorded on film.
Bowerbirds
DISNEYLAND’S A LIE. Mickey Mouse, for instance, isn’t a mouse at all, but a costume with a person inside. The architecture, too, is deceptive. That giant castle isn’t as tall as it looks, because designers deployed something called forced perspective, making the windows near the top smaller so they seem farther away.
It’s some next-level sneakiness that the great bowerbird would find laughable. It was deploying its own visual tricks long before Walt Disney came around. The male great bowerbird constructs a beautiful tubular structure out of twigs, depositing bones and snail shells to make courts at either end. He arranges these in a very specific way, though, opposite of what’s going on in Disneyland: By deploying forced perspective, the male bowerbird actually makes his court look smaller. Also very unlike Disneyland, he does it to help him get laid.
In Australia and New Guinea, 24 species of bowerbird undertake some of the most bizarre mating rituals among avians. Some males build big cave-like structures—known as bowers—out of sticks, clearing a court in front where they hoard objects of very particular colors. A pile of blue junk, for instance, might include berries and the odd piece of blue plastic. Other bowerbirds build simpler, smaller “avenue” bowers—two rows of sticks arranged vertically to create a kind of tunnel.
The male great bowerbird is in this latter camp. Among the builders, his bower is kind of meh if I’m being honest: He chooses drab rocks and snail shells and bones to decorate his court.
The female bowerbird doesn’t really care, though. Here’s how the seduction goes down. The male flutters into a bush above his bower and calls to the female. Should she join him, he’ll drop down to his crib and take up position in one of the courts. “He starts strutting about and then she goes inside [the bower], and he struts about a bit more and makes a funny sound,” says evolutionary ecologist John Endler of Australia’s Deakin University. “It’s sort of like, tick tick tick tick.”
Now pretend you’re a female great bowerbird. The tight walls of the structure direct your attention to the court. If the male had placed objects of any size willy-nilly throughout the court, to your eye the court would seem fairly large: Objects farther away of course look smaller and give a sense of depth.
Notice the arrangement of larger objects farther away from the bower. This tricks the female into thinking that the court is smaller or, at the very least, that she’s on acid.
But that’s not what you see here. The bones and stones and such all look to be the same size because the male is tricking you. He’s placed the larger objects farther away from your eye and the smaller ones closer to you. “The effect of that is to make a more even pattern,” says Endler. “It would probably have an effect of making the court look smaller and therefore the bird itself might look larger.” He’s using the art of forced perspective to show off.
That’s not the only visual illusion the bowerbird uses. In another part of the mating process, he takes up a position off to the side of the bower entrance, popping just his head into view to wave objects at the female, real needy-like. The males who find the best, most colorful objects are the most desirable, after all.
Here’s where it gets interesting: While the outside of the bower looks fairly plain, the male has painted the inside red by chewing up bits of plants and fruits. He didn’t do that to get the female in the mood—he’s actually messing with her color vision. The male picks up a typically colorful object, which she sees set against the dullness of the court, and gives it a wave. He throws the object away, grabs a new one, and gives that a wave. He’ll also flash the vivid crest on the back of his head every so often for good measure.
All the while the female’s eyes are adjusting to the red paint lining the bower. As this is happening, her retina is comparing the data from its red-sensitive cones and green-sensitive cones in order to sense colors.
But the paint is overwhelming the red cones. “The effect on the bowerbird is she’s going to become less sensitive to red light, which means that green objects are going to be brighter,” Endler says. The battle between red cones and green cones has tipped toward the greens. (Human peepers work the same: You can see how tightly green and red are paired in your eyeball with this demo. By staring at green stripes, you desensitize your green cones, so when you look at something white, red magically replaces the green.) Indeed, the male will wave a disproportionate amount of green objects to red ones in order to impress her.
After an average of a minute or so of all this, the male will run around the back. If the female is receptive, she’ll let him mate with her. If not, she’ll just burn him and fly away.
Males don’t only have to worry about how to best seduce the ladies. Opportunistic males will often tear down their neighbors’ bowers or steal objects left unattended. This is relatively rare if bowers are nice and spaced out, perhaps over a half mile apart, but as density increases, so does the marauding. “There’s the other side of the story: If you’re going away to maraud someone, your own bower might get ruined,” Endler says. “Sounds a lot like politicians, doesn’t it?”
Between all of the seduction and ganking each other’s stuff, you might think the great bowerbird would be in serious danger of ending up in something’s mouth. After all, the perk of being a bird is you can avoid the scrum on the ground. But incredibly, in the 20 years combined that Endler and a colleague have observed these creatures in the wild, never once have either seen a predator nab a bird. Great bowerbirds are sharp-eyed and more than spry enough to dodge something like a lumbering monitor lizard.
Killer Cows
Between 1993 and 2015, cattle killed 13 people who were out for walks in the United Kingdom. Dozens more walkers received broken bones or other injuries from the animals.
Murderous cattle are an understudied phenomenon, say veterinarian Angharad Fraser-Williams and other researchers at the University of Liverpool in the United Kingdom. So they scoured news articles and scientific literature to learn about cattle attacks over two decades. They turned up some advice for people wishing to avoid a fight with a bovine. First: don’t try to save your dog.
In the United Kingdom, the authors explain, public paths in the countryside often cross through farmland. This means people out for a stroll may find themselves face-to-face with herds of grazing cattle. To find out how often these encounters turned ugly, the researchers hunted through scientific literature for papers including the terms “cow” or “bovine” plus “attack” or “injury.” When they narrowed the results down to papers about attacks on humans, they were left with only eight.
Likewise, they searched UK newspaper archives from 1993 to 2013. This time they turned up 89 relevant articles. They also searched the Internet for British webpages about “best practice for walking among cattle.”
Much more dangerous than simply hiking through the countryside, it turned out, is working with cattle directly. Dairy and beef farmers, vets, and slaughterhouse workers incur the most cattle-caused injuries. The most common injuries are broken bones from being kicked, but there are also deaths from being trampled or just accidentally walked on by the heavy animals. An American study looked specifically at attacks by bulls, rather than cows. Most of these cases were in the United States. Over 28 years, the authors found 149 fatal incidents.
Among walkers in the British countryside, the University of Liverpool researchers found reports of 54 cattle attacks over the two decades of their study. Of these, 13 resulted in a fatality. The most deadly year was 2009, when there were 13 attacks and 4 deaths. Injuries included “fractures to arms, ribs, wrist, scapula, clavicle, legs, lacerations, punctured lung, bruising, black eyes, joint dislocation, nerve damage and unconsciousness.”
The scientific literature revealed some reasons cattle might attack. One is maternal behavior. Mother cows see humans as a threat to their calves, and they may take action to protect a calf if a person gets too close.
Even more threatening to cattle than humans, another study found, are dogs. Cattle are especially vigilant when dogs are nearby.
The newspaper articles bore this out. About two-thirds of the cattle attacks involved dogs. In at least two cases, people were killed while trying to protect their dogs, which had spooked the cattle.
The researchers found plenty of advice online about how to walk safely through cattle, some of it inconsistent: Walk boldly through the middle of a herd. No, go around the herd instead. Carry a walking stick. Keep quiet and move calmly. Wave your arms and shout if the cattle threaten you.
Certain pieces of advice come up often, though, and seem wise based on what the researchers found: Be careful around mothers and their calves. Keep your dog close. And if cattle charge your dog, let go of its leash—don’t try to pick it up or protect it.
Egrets and Alligators
For Florida’s egrets, the advantage of nesting in trees above alligators is clear: if you have a quarter-tonne of hungry top predator beneath you, lesser predators, especially the tree-climbing sort that eat egrets, will stay away.
What, though, do alligators get from this relationship? Well, it turns out the alligator-egret pact is more Faustian than it appears because every now and then the egrets push a chick out of their nests and the alligators eat it.
Sometimes, if not enough chicks are forthcoming, the alligators slap the trees with their tails until one appears, and scientists studying one of nature’s more unlikely symbiotic relationships have concluded that although both sides benefit, it is a grim trade.
In the everglades, wading birds nest on islands in vast numbers. Biologists have put fake alligators on to some islands and shown that birds are more likely to pick them, presumably because the alligators scare away racoons that can ravage nests.
“In order to understand the ecology of this relationship we needed to know what happens to both partners,” said Lucas Nell, from the University of Florida. “Certainly, alligators are not being altruistic in any way. They’re very tender parents, but other than that they do not show a lot of compassion,” he said. “There’s a lot of research showing alligators will move significant distances to get to food sources, and these nesting colonies are very conspicuous, smelly and noisy.”
Crucially, the birds’ hygiene is far from their most unappealing habit: they also eject chicks from their nests if they think they have too many.
At the same time “siblingcide”, where the stronger chicks kill off the weaker, is common. The result, particularly when combined with the observed habit among some alligators of shaking the tree, is a steady rain of juicy chicks. “It turns out that in prolific years it can be a pretty amazing amount of food, enough to support most of the breeding females over the course of the dry season,” said Mr Nell, whose research is published in the online journal Plos One. “There are tens of thousands of nests, and they provide a stream of nutrients.”
Mr Nell’s research has shown that so significant is the effect of this fluffy manna, that a 2m alligator living beneath a bird colony weighs on average 3kg more than one elsewhere.
“It’s less like hiring a bodyguard, more like keeping a psychopathic murderer in your yard to scare burglars,” he said.
Toxoplasma and Rage
Road rage and other acts involving a sudden loss of self-control could be linked to a parasite spread by cats.
Infection by Toxoplasma gondii doubles the chances of suffering bouts of uncontrollable anger, a study found.
People with intermittent explosive disorder (IED) are liable to display outbursts of violent rage which are disproportionate to the provocation received — for instance, when annoyed by another driver on the road.
Scientists who assessed 358 US adults found that 22 per cent of those diagnosed with IED also tested positive for T. gondii. In non-infected individuals only 9 per cent had the condition.
Emil Coccaro of the University of Chicago, the lead researcher, said: “Our work suggests that latent infection with the parasite may change brain chemistry in a fashion that increases the risk of aggressive behaviour. We do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues.”
Many people are believed to carry the parasite, found in cat faeces and contaminated food, without realising it.
Each year about 350 cases of toxoplasmosis are reported in England and Wales, but experts believe the number of infections could be a thousand times greater. Some estimates suggest that up to a third of people in the UK will be infected at some point in their lives.
Often, the parasite causes no symptoms, but it can lead to miscarriages, birth defects, and cause serious illness in people with weak immune systems.
It has been linked to psychiatric conditions including schizophrenia, bipolar disorder and suicidal behaviour. Roughly a third of those in the study had IED, another third had some other psychiatric condition such as depression or personality disorder, and the remainder were healthy individuals with no history of mental problems. Toxoplasmosis-positive individuals scored significantly higher on measures of anger and aggression.
Co-author Royce Lee said: “Correlation is not causation, and this is not a sign that people should get rid of their cats. We don’t yet understand the mechanisms involved. It could be an increased inflammatory response, direct brain modulation by the parasite, or even reverse causation where aggressive individuals tend to have more cats or eat more undercooked meat. Our study signals the need for more research and more evidence in humans.”
IED is thought to affect up to 16 million Americans, said the scientists whose findings are reported in the Journal of Clinical Psychiatry.
Feral pigs
Feral pigs are wreaking havoc across the globe. But it isn’t easy to outwit these brainy beasts. RODNEY WOODSON never set out to be a pig trapper. He joined the Tennessee Wildlife Resources Agency because he was passionate about conserving water birds. But that was before the hogs rocked up, with their high libidos and low cunning.
Across the world, and especially in the southern US, feral pigs are a problem. Marauding hordes of swine are destroying crops and sensitive natural environments, causing traffic accidents and spreading disease and parasites. They have even dug up cemeteries. The US Department of Agriculture estimates the damage at $1.5 billion a year.
As so often with invasive species, this is a problem of our own making. Wild pigs were introduced to the US by Spanish settlers hundreds of years ago, but weren’t a cause of widespread concern until the 1990s, says zoologist Jack Mayer at the Savannah River National Laboratory in South Carolina, when cable TV ads began promoting the animals as an exotic alternative hunting target to turkeys and deer. In 1999, Tennessee established a hog hunting season, and soon enterprising landowners were stocking up. That ushered in “an explosion of new hog populations” across the state, says Chuck Yoest, coordinator of the Tennessee Wild Hog Eradication Action Team, part of the agency that Woodson works for. In 2011, the state reclassified pigs from big game to destructive pests.
The pigs’ supercharged reproduction rate isn’t helping. A sow may produce two or more litters of typically five or six pigs every year, making it nearly impossible to cull all the individuals in an area at once. Pig population models show that clearing an area requires removing 70 per cent of the animals “year after year after year, until you drive that population to extinction”, says Mayer.
In Texas, some landowners now offer wealthy customers the opportunity to machine-gun pigs from a helicopter for as much as $1000 an hour. Other communities have called in teams of sharp shooters. But critics say that these methods of pig control are not just inhumane, but ineffective. For a start swine are fast: they can run at up to 50 kilometres an hour. They can also respond to hunting pressure in surprising ways, for example switching between nocturnal and diurnal living patterns. “They’re a pain in the backside, but they are interesting critters,” says Mayer.
Traps of the sort Woodson lays are generally thought to be the least bad option in dealing with the pigs. But porcine intelligence makes trapping a full time job. Pigs have been shown to beat chimps when it comes to IQ, are whizzes at navigating complex mazes and can manipulate cursors on a screen by controlling a joystick with their snout. It means in simple traps they soon work out how to jump over short fences and climb taller ones, for example by gaining purchase at a corner.
Boar busting
Woodson’s first tactic was to play the long game and put the pigs under surveillance. He installed cameras near baited traps, so pest control officers could examine pictures to see how many animals came by, and when. Once they knew which traps were frequented by the hogs, they could stake them out, hiding near a trap and triggering its gate at the right moment.
This was by no means a perfect strategy. It took lots of time and people, and although pigs can’t see well, they have a keen sense of smell. If they picked up the scent of a human, the pigs wouldn’t approach a trap.
So in his latest iteration Woodson has gone wireless, using solar-powered cameras overlooking a circular enclosure with 1.4-metre-high fences – high enough for pigs to have trouble climbing them, and with no corners to aid escape. When a motion sensor detects a pig-sized animal, it sends Woodson an email. From his own home, he can watch a real-time feed of the trap and at the right moment flip a switch to drop the gate.
This human check is critical, Woodson says. If even one pig from a group is left uncaught, it may learn to avoid similar traps. Though maternal education in pigs hasn’t been studied rigorously, Woodson’s experience suggests that if it’s a sow, it may train its offspring to do the same.
His creative trapping is bearing fruit: the record for one of the traps is 52 swine at once. And the wireless approach is generally becoming more popular. Landowners can buy commercial versions of remotely operated traps, including the $6000 Australian model known as the “Boar Buster”.
But the story is far from over. Eager for more game, a few unscrupulous landowners are still trafficking pigs to Tennessee from neighbouring states, creating fresh pockets of infestation. Longer-term, climate change may also exacerbate things, at least in Europe. Last year, researchers at the University of Veterinary Medicine in Vienna, Austria, predicted that feral pig numbers there will surge during mild winters, as more food becomes available.
So others are thinking beyond traps. There is the “Judas pig” method, in which, when a group of pigs is culled, a sow is left alive and tagged with a GPS collar. She then does the hard work of finding another, doomed, tribe – at which point shooters are sent in. Then there are chemical approaches such as hog-specific poison or contraceptives. Later this month, trappers and conservationists will brainstorm new ideas in Myrtle Beach, South Carolina, at the international Wild Pig Conference.
Meanwhile Woodson can’t stand idle. His latest trap has an oblong pen with two gates directly opposite each other, giving the pigs the illusion of a safe passage. The hogs in his patch are wise. It is a brutal business, and there’s no time for complacency.
Webcams and Brutal Nature
The osprey cam at the Woods Hole Oceanographic Institution is trained on a nest near the Massachusetts seaside, and the pair that call it home are now waiting for three eggs to hatch. But for the first spring in a decade, the camera is dark, and a note on the institute’s website offers only a two-sentence explanation.
“Regrettably, the cam will not be operating this season due to the increasingly aggressive actions of certain viewers the last two years,” it begins.
That is a staid reference to cam fans whose emotions about the nest morphed into vitriol — and fighting words. When the osprey mother began neglecting and attacking her chicks in 2014, anxiety exploded among some viewers, as did demands that the institution intervene to save the baby birds. When the same thing happened in 2015, the public passions took a more personal turn.
“It is absolutely disgusting that you will not take those chicks away from that demented witch of a parent!!!!!” one viewer emailed to Jeffrey Brodeur, the communications specialist who ran the camera. Another wrote: “I realize this is nature, but once you put up a cam to view into their worlds it is no longer nature. You have a responsibility to help n save when in need.”
Bird-nest cams have become hugely popular, and spring is when they’re full of action. Millions of viewers log on to see live-streamed egg-laying, egg-incubating and chick-hatching. Along the way, many become attached to the little birds, eager to see them spread their wings and fly.
But nests are also nature, and nature can be nasty. Last month, a Pittsburgh cam’s bald eagles made national news when they fed a small cat to their eaglets. Many chicks don’t survive their first year: Some starve to death, their carcasses decaying for all the Internet to see. Some are preyed upon by hawks or crows or cats. Some are slain by their nestmates.
And some viewers just can’t handle the tragedy.
Brodeur, who had taken on the camera as a pet project, weathered the ire of the 2014 season and adhered to a policy of refusing to intervene, as advised by osprey experts. The drama revved up again last summer, when the osprey parents weren’t bringing in enough fish for the two chicks. One day in mid-July, Brodeur said, his phone “just starts blowing up.” He looked at the nest, which is on a platform right outside his second-floor office window.
“There’s a lot of wing-flapping going on,” he recalled. “The younger of the two had worked its way to the edge, and the older one went for the kill. Shoved it out of the nest. And it’s all live on camera.” Brodeur retrieved the chick from the brambles below, but it died of malnourishment at a wildlife center that night. Soon, the other chick began growing weaker. Viewer calls and emails started pouring in, some bordering on threatening. “It was definitely, if you can’t do something, we’ll do something for you — dot, dot, dot,” Brodeur said.
The Woods Hole experience isn’t unusual, and it’s the reason most nest cam operators publish policies on when they’ll intervene. One Montana osprey cam reminds viewers that it “is not a Disney movie.” The Cornell Lab of Ornithology, which views its many cams as key tools to recruit new bird-lovers, occasionally puts a warning on the screen when things get gruesome, along with a little context, said Charles Eldermire, who manages the cams.
The lab might, for example, explain that “hatching asynchrony” — when one chick hatches before another — can produce one stronger chick that hogs resources and starves out the others. One time, Eldermire said, a hawk “squeezed the life” out of a starling chick on camera, prompting a warning to viewers that they’d see predation. The lab doesn’t help struggling birds unless their woes are human-caused, like when a chick is tangled in fishing line.
“It’s like watching ‘Game of Thrones.’ You know somebody is going to die, but you don’t know who or how or why. You know one possibility is someone’s not going to die,” Eldermire said. But, he added: “For people that want us to intervene, all they’re focused on is, ‘We watched this egg get laid, we watched it hatch, and we didn’t come here to watch it die.’”
Harriet and M15, the adult eagles who inhabit the nest featured on the Pritchett family’s nest cam in Florida. (Southwest Florida Bald Eagle Cam)
In 2014, when the chicks featured on a bald-eagle cam in North Fort Myers, Fla., weren’t getting much to eat, some viewers decided to take matters into their own hands. Under cover of darkness, they headed to the nest site and tossed meat into it — a roast, to be specific. The viewers were never identified, but their actions prompted a scolding on the Southwest Florida Eagle Cam’s Facebook page, reminding them that feeding bald eagles, which are protected, is a federal offense.
That was one example of the “crisis P.R.” that Ginnie Pritchett McSpadden says she has dealt with since her family launched the uber-popular cam four years ago.
They started out with an eagle pair they named Ozzie and Harriet. Then Ozzie was hit by a car, and while he was at a rehab center, another male took his spot. When Ozzie came back, the males fought, and Ozzie succumbed to his injuries. Viewers freaked out, and that was another lesson for the Pritchetts: Don’t name the birds. “When we named them, people got a very, very human emotional attachment to them,” said McSpadden, who says she generally loves running the cams. “We realized how negative that can be if something goes wrong.”
Other incidents that have caused an uproar: In 2013, the eagles brought a cat into the nest; McSpadden tried to calm viewers by referring to it on a YouTube video as a UFO, or “Unidentified Food Object.” Two seasons in a row, eaglets died and the mother ate their carcasses. In 2013, bald eagles in North Fort Myers, Fla., brought a UFO, or "Unidentified Food Object," into their nest. (Southwest Florida Eagle Cam) “I won’t lie when I say people have said we’re the worst people in the world because we won’t go save the eaglet that hasn’t eaten in three days,” McSpadden said.
In February, a chick known as E8 was being picked on by its sibling, which the cam noted on its Facebook page is not uncommon. “If you become emotional, we ask you to turn off the cams,” they wrote.
One commenter responded like this: “I for one will not stop fighting to get e8 removed from this nest with every ounce of strength I have. … Shame on all involved!!!”
Last summer, when people started promising to bring ladders to the Woods Hole Oceanographic Institution’s campus to pluck the hungry osprey chick from the nest, Brodeur caved.
“Finally, I crossed my Rubicon: I called the state wildlife biologist,” said Brodeur, who, like his oceanographer colleagues, is not a bird expert. “And he was like, ‘Listen, the rules are different. You have a camera on it, and the thing’s going to starve to death on prime time.’”
They removed the chick — and Brodeur knew the nest cam was over.
“All these people who were my enemies were now my best friends, and they were crying victory. I had intervened. They had influenced me,” he said. Also, he said, “I knew I had set a precedent.”
Brodeur says he liked running the nest cam and interacting with viewers — most of them. But he had a full-time job that was getting hard to juggle with the flood of osprey-related calls and emails.
The funny thing is, he said, no one’s seemed to mind that he shut it off. They’ve moved on to another cam, he figures, and will be blissfully oblivious to whatever tragedy plays out at the institution’s nest this year.
“These cameras, in my opinion, aren’t about nature,” he said. “It’s about the people that are watching and how they view nature.”