Giant Anteaters Can Kill People

Friday, August 15th, 2014

Don’t get complacent. Remember, giant anteaters can kill people:

In a new case report, scientists detail a gruesome anteater attack that left one hunter dead in northwestern Brazil, just two years after another man was killed in a similar confrontation with one of the long-nosed creatures. While such incidents are rare and anteaters usually avoid contact with humans, the attacks should serve as a warning to humans encroaching on anteater turf, the authors wrote in the journal Wilderness and Environmental Medicine this month.

Giant anteaters, which live in savanna-like fields in South America and Central America, are the largest of the four living anteater species, and can grow up to 7 feet (2.1 meters) long in adulthood. They have four sharp claws on both of their forelimbs that they can use to quarry anthills and termite mounds — and, apparently, to inflict fatal wounds on humans.

The creatures assume a standing position when they feel threatened, sometimes referred to as an “anteater’s hug.” On the Internet, anteaters standing messiah-like with arms outstretched have become the benign stars of memes. But in the wild, an anteater posed like it wants a hug is really throwing up a red flag.

On Aug. 1, 2012, a 47-year-old man, who lived in a rubber plantation in Guajará County in Brazil’s Amazonas State, near the border with Peru, went hunting with his two sons. Their dogs cornered an adult giant anteater and it went into its standing pose, wrote the researchers, led by Vidal Haddad Jr., an associate professor at Sao Paulo State University’s Botucatu Medical School.

The man approached, but was worried about accidentally shooting his dogs, so he opted for a knife instead of his rifle. But before the man could make a move, the anteater “grabbed” him with its forelimbs, Haddad and colleagues wrote. The man’s sons eventually freed him from the anteater’s clutches, but he was severely wounded and bled to death at the scene. One of the sons, who also suffered some slight injuries, shot the anteater to death.

When doctors and forensic investigators later examined the victim, they found that he had bruises and lesions on the left side of his neck, two 1.5-inch (4 cm) puncture wounds in his left arm, eight puncture wounds in his left thigh and abrasions on his right thigh. An autopsy revealed severe damage to his left femoral artery, a large artery in the thigh, according to the case report.

A similar incident occurred in 2010, when an anteater attacked a 75-year-old man who was hunting in Brazil’s Mato Grosso state, the scientists noted. The victim in this case, too, suffered a grave injury to his femoral artery and bled to death. His death was reported in the local media at the time, but scientists did not formally document the animal attack, the authors wrote.

That puts a new spin on the classic Monty Python vocational guidance counsellor sketch (which starts one minute in):

How to Fight a Dog (and Win)

Thursday, August 14th, 2014

Weapons Man explains how to fight a dog (and win), starting with these facts about dogs:

  1. Anybody can fight any dog and win.
  2. Normal dogs do not fight to the death.
  3. Adults killed by a single dog are extremely rare outliers.
  4. The only part of the dog that can hurt you is the teeth.
  5. The dog is extremely vulnerable in the neck area.
  6. If it is a fight to the death, expect to get bitten… don’t let it distract you.

Dogs fight like pack animals:

They run around and try to distract you and get behind you. A vicious dog, behind you, may go for a hamstring. Dogs make darting, slashing attacks and break contact. Dogs fight dogs naturally, but they do not fight to the death, only for dominance. A human who has been knocked down by a dog or a pack of dogs may trigger predation behavior, but one who remains upright and takes the fight to the dog will always prevail.

It helps to have protection on your weak hand forearm; you can then offer that as a target for the dog. Even without protection, offering the weak hand leaves the dog vulnerable to your strong hand. If you get him to snap at that, you have him right where you want him. Get his neck with your strong hand and overturn him.

Your objective is to get him on his back, with you astride him, and both hands on his neck. In this position he cannot bite you and you can choke him out. If you don’t want to kill the dog, you can just choke him. If you do want to kill him, crush his windpipe; end of dog. In fact, in most cases, the dog will give up when overturned by someone who has a grip on his neck.

[...]

Odds are you outweigh him; you have opposable thumbs; you are much more intelligent; you are the apex predator.

The Spy Who Loved Frogs

Monday, August 4th, 2014

Herpetologist Edward Taylor led the life of an old-school, adventuring naturalist:

As [Rafe] Brown made his career studying biodiversity in the Philippines over the next two decades, he could not escape Taylor’s long shadow. The elder herpetologist had logged 23 years in the field over his lifetime, collecting more than 75,000 specimens around the world, and naming hundreds of new species.

There is a darker side to Taylor’s legacy, however. He was a racist curmudgeon beset by paranoia — possibly a result of his mysterious double life as a spy for the US government. He had amassed no shortage of enemies by the time he died in 1978. An obituary noted that he was, to many, “a veritable ogre — and woe to anyone who incurred his wrath”. More damaging, perhaps, were the attacks on his scientific reputation. After the loss of his collection in the Philippines, many of the species he had named were declared invalid or duplicates. The standards of taxonomy had advanced beyond Taylor’s quaint descriptions, and without the specimens to refer to, his evidence seemed flimsy.

Mouse Utopia

Wednesday, July 30th, 2014

In the late 1960s, John B. Calhoun placed four breeding pairs of mice into a Mouse Utopia, free of predators and full of food and water.

The population grew exponentially — for a while. For the first 620 days, the population doubled every 55 days. Then, the doubling slowed down. Then, growth stopped, and the dysfunction began.

In the original paper, Death Squared: The Explosive Growth and Demise of a Mouse Population, Calhoun draws these conclusions:

The results obtained in this study should be obtained when customary causes of mortality become markedly reduced in any species of mammal whose members form social groups. Reduction of bodily death (i.e. ‘the second death’) culminates in survival of an excessive number of individuals that have developed the potentiality for occupying the social roles characteristic of the species. Within a few generations all such roles in all physical space available to the species are filled. AT this time, the continuing high survival of many individuals to sexual and behavioural maturity culminates in the presence of many young adults capable of involvement in appropriate species-specific activities. However, there are few opportunities for fulfilling theses potentialities. In seeking such fulfilment they compete for social role occupancy with the older established members of the community. This competition is so severe that it simultaneously leads to the nearly total breakdown of all normal behaviour by both the contestors and the established adults of both sexes. Normal social organization (i.e. ‘the establishment’) breaks down, it ‘dies’.

So far, that sounds almost like Peter Turchin’s notion of elite overproduction.

Calhoun continues:

Young born during such social dissolution are rejected by their mothers and other adult associates. This early failure of social bonding becomes compounded by interruption of action cycles due to the mechanical interference resulting from the high contact rate among individuals living in a high density population. High contact rate further fragments behaviour as a result of the stochastics of social interactions which demand that, in order to maximize gratification from social interaction, intensity and duration of social interaction must be reduced in proportion to the degree that the group size exceeds the optimum. Autistic-like creatures, capable only of the most simple behaviours compatible with physiological survival, emerge out of this process. Their spirit has died (‘the first death’). They are no longer capable of executing the more complex behaviours compatible with species survival. The species in such settings die.

You may be wondering about his references to the first death and the second death. They’re Biblical references — with which he opens his scientific paper — in the Proceedings of the Royal Society of Medicine in 1973:

I shall largely speak of mice, but my thoughts are on man, on healing, on life and its evolution. Threatening life and evolution are the two deaths, death of the spirit and death of the body. Evolution, in terms of ancient wisdom, is the acquisition of access to the tree of life. This takes us back to the white first horse of the Apocalypse which with its rider set out to conquer the forces that threaten the spirit with death. Further in Revelation (ii.7) we note: ‘To him who conquers I will grant to eat the tree of life, which is in the paradise of God’ and further on (Rev. xxii.2): ‘The leaves of the tree were for the healing of nations.’

Riiiigghhhht.

Anyway, the Mouse Utopia experiment is usually interpreted in terms of social stresses related to overcrowding, but, Bruce Charlton points out, there’s another explanation:

But Michael A Woodley suggests that what might be going on is mutation accumulation, and deleterious genes generating a wide range of maladaptive pathologies, incrementally accumulating with each generation; and rapidly overwhelming and destroying the population before any beneficial mutations could emerge to ‘save; the colony from extinction.

So the bizarre behaviours seen especially in Phase D — such as the male ‘beautiful ones’ who appeared to be healthy and spent all their time self grooming, but were actually inert, unresponsive, unintelligent, uninterested in reproduction — are not adaptations to crowing, but maladaptive outcomes of a population sinking under the weight of mutations.

The reason why mouse utopia might produce so rapid and extreme a mutation accumulation is that wild mice naturally suffer very high mortality rates from predation.

Chimps Like African Beats

Wednesday, July 23rd, 2014

Research has shown that chimps don’t like human music — but those studies all used Western music:

“Although Western music, such as pop, blues and classical, sound different to the casual listener, they all follow the same musical and acoustic patterns. Therefore, by testing only different Western music, previous research has essentially replicated itself,” the authors wrote. The study was published in APA’s Journal of Experimental Psychology: Animal Learning and Cognition.

When African and Indian music was played near their large outdoor enclosures, the chimps spent significantly more time in areas where they could best hear the music. When Japanese music was played, they were more likely to be found in spots where it was more difficult or impossible to hear the music. The African and Indian music in the experiment had extreme ratios of strong to weak beats, whereas the Japanese music had regular strong beats, which is also typical of Western music.

“Chimpanzees may perceive the strong, predictable rhythmic patterns as threatening, as chimpanzee dominance displays commonly incorporate repeated rhythmic sounds such as stomping, clapping and banging objects,” said de Waal.

Chimpanzee War

Friday, June 27th, 2014

Chimpanzees go to war — and eat their fallen foes:

Chimpanzees Hunting Colobus Monkey

Friday, June 20th, 2014

Chimpanzees aren’t gentle herbivores. Watch them hunt a Colobus monkey, as a team:

In Pursuit Of An Ancient Pursuit

Monday, June 9th, 2014

Back in 1978 Michael Baughman wrote about trying to run down a deer Indian-style for Sports Illustrated:

A large stone in each hand, I trotted down to it through the star thistle. Breathing deeply, I stood in the warm shade on the uphill side. The thicket was even denser than I remembered, much too thick to see into. I tossed the first stone, shook the slender trunk of a willow and yelled. There was a heavy thrashing deep within the thicket, then a whirring of wings. A covey of 30 or 40 valley quail burst out in all directions. A pheasant came behind them, a cock this time, and then the deer. I heard the deer before I saw it, crashing out of the bottom end. I circled around the top to avoid the swampy area. It was a young buck.

I dropped the second stone and started after him. He had a 40- or 50-yard head start, going south, parallel with the ditch above us, and his head was turned to watch me as he picked up speed. I held my pace and angled back to the firmer footing along the ditch.

He was 200 yards ahead and gaining ground. I maintained my pace. As long as I stayed within a quarter mile of him I would have a chance of running him down.

The springy, almost jumping gait of the buck was beautiful to see. His raised tail and rump were startlingly white in the dusty heat, and small clouds of powdery dust rose like smoke behind him.

I kept my pace. I’d covered better than a quarter mile by now without tiring. He stayed below the ditch, heading, as I had hoped he would, for the next thicket along the way.

By then I was sweating hard, but my legs were fine. As he entered the thicket, I was little more than 300 yards behind. I could see him in the willows, see the white rump, and then even closer, the turned head with its brown, glassy eyes staring back at me in fright.

A hundred yards away I yelled, and this time he broke out from the top end, raced straight up the hill and cleared the irrigation ditch with one incredibly graceful bound. This was lucky for me. By coming up the hill, he had actually shortened the distance between us.

Once across the ditch, he picked up speed again. The next mile or two, I knew, would be the hardest. But after that his fright would work to my advantage.

He started up the slope on the other side of the ditch, stopped, turned again to look, then headed straight for the nearest thicket. I had to step up my pace. My legs hadn’t begun to tire, but my breath was coming so hard that my side ached. Two hundred yards above me, and twice that far ahead, the buck reached the sparse thicket near the long-deserted ranch house with the rusted Model T in the yard.

Twenty minutes later the buck was exhausted:

I was only 10 yards away from him. He took a tentative step, but his head sank. He could go no further. I stopped where I was and talked to him soothingly.

Flies circled over his back, at least a couple of dozen of them, but he was trembling so severely that they couldn’t light. His wide brown eyes never blinked or left my own the whole time I was talking to him.

When a full minute had passed that way, he had rested enough to raise his head. The trembling eased. The flies alighted.

I walked up slowly and touched his sweaty flank. He started away, jerkily and graceless for the first few steps, then with increasing confidence, and all the way his head was turned to watch me.

Catch-and-release persistence hunting never caught on.

A Toothy Torpedo Covered in Sandpaper

Sunday, June 8th, 2014

You might describe a shark as a toothy torpedo covered in sandpaper:

A shark’s skin is covered in millions of microscopic denticles, rigid tooth-like scales that jut out from the soft skin beneath. By disrupting the flow of water over the fish’s skin, it is thought, the denticles reduce drag, making for a more efficient swimmer. But to really empirically understand how the denticles do their job, you need to see how different sorts of skin coverings affect the fluid dynamics as water washes over the skin of swimming fish. You can’t take a real shark and give it new skin, so Harvard University researchers Li Wen, James C. Weaver, and George V. Lauder created artificial shark skin instead. They manufactured it using a 3D printer.

Artificial shark skin with rigid denticles attached to a flexible membrane

Lauder’s group then subjected their 3D-printed faux skin to a series of tests in water. They found that it managed to reduce drag by 8.7% when the water flowing over it moved slowly, which is consistent with the thought that denticles reduce drag. But in faster currents, the denticles actually increased drag by 15% compared to a smooth sheet. That might seem surprising at first, but sharks don’t swim in a straight line, they wriggle their bodies. As soon as the researchers started wriggling their artificial skin, the swimming again become more efficient: swimming speed increased by 6.6% and the energy expended was reduced by 5.9%.

Pinnipèdes

Saturday, May 10th, 2014

Pinnipèdes is a 3D animated short about elephant seals:

Eagle Huntress

Friday, April 18th, 2014

What is best in life?

The open steppe, a fleet horse, falcons at your wrist, and the wind in your hair.

So, 13-year-old Ashol-Pan might say — although the Mongolian girl hunts with an eagle:

Ashol-Pan 01

Ashol-Pan 02

Ashol-Pan 03

Ashol-Pan 04

Ashol-Pan 08

Ashol-Pan 09

Hawk, Dove, Bourgeois

Tuesday, April 8th, 2014

Game theorists have long turned to the classic hawk-dove game to study conflict:

‘Doves’ are individuals who never fight. If attacked, they run away. ‘Hawks’, on the other hand, are always ready for violence and will attack anybody who has something that they want. In a country populated by meek doves, the hawk strategy does very well. But as hawks become more numerous at the expense of doves, they spend more and more time fighting and killing each other.

There is, however, a simple modification of the hawk strategy that is superior to both hawks and doves: playing ‘bourgeois’. First, you declare a resource item — a herd, a piece of cropland — as your private property (hence the ‘bourgeois’ designation). Then you signal that you are willing to defend it no matter what it takes. Again, this is not rational in the narrow sense. You must be willing to escalate conflicts to the point where your life is at stake, even though your life is worth incomparably more than the disputed property. But again, in evolutionary terms, the strategy is a winner. While the hawks overreach, getting embroiled in self-destructive conflict, the bourgeois steadily divide the spoils among themselves, fighting only to defend their property against hawks. In the long run, the bourgeois always replace the hawks.

I’m no ornithologist, but there has to be a notoriously territorial bird we could use to extend the metaphor, doesn’t there?

Personality Predicts Social Learning

Wednesday, March 19th, 2014

Researchers conducted a three-year study of how personality interacts with social learning — in wild baboons in Namibia:

Carter and her colleagues had given all the baboons “personality tests” to measure two traits, boldness and anxiety. They assessed boldness by looking at a baboon’s response to a new food (such as a hard-boiled egg dyed green); the bolder the individual, the more time he or she spends inspecting a new food. They assessed anxiety by presenting the baboons with a taxidermied venomous snake; in this test, more anxious individuals spend more time investigating the potential threat. Boldness and anxiety are stable personality traits and are independent in baboons, meaning a bolder baboon is just as likely to be anxious as a shy baboon.

After figuring out where individual baboons fell on these two personality traits, the researchers looked at whether the traits were related to the time spent watching a demonstrator or the subsequent ability to then solve the task being demonstrated.

They found bolder and more anxious individuals were more likely to learn about a novel foraging task from another baboon — despite the fact that shy baboons watched the demonstrators just as much as bold baboons, and calm baboons paid even more attention to the demonstrators than anxious baboons. This means that an individual’s ability or interest in watching a demonstrator does not necessarily translate to then solving the task. All personality types seemed to collect social information, but bolder and more anxious baboons were better at using it.

Carter thinks that bold baboons may show more social learning not because they are smarter or better at learning this type of information, but because they are more willing to interact with something new. “I imagine that watching another individual manipulate a novel food requires less boldness than manipulating a novel food directly,” she says. “It’s likely the shy baboons were just too shy to handle the food, even after watching a demonstrator.”

Caribbean Reef Shark

Monday, March 17th, 2014

A scuba diver was about 70 feet down, in the Western Caribbean Sea, culling lion fish, when a Caribbean reef shark attacked — and just kept coming:

Yosemite Bears and Human Food

Wednesday, March 12th, 2014

Researchers performed isotope analysis of hair and bone samples to study Yosemite bears’ changing diets over the past century:

Yosemite National Park was established in 1890, and Hopkins obtained samples from bears killed between 1915 and 1919 to represent the earliest time period. In those early years, bears were attracted to garbage dumps in the park and were often killed when they became a nuisance. Visitors liked to see bears, however, and in 1923 the park began intentionally feeding bears where visitors could watch them. The last artificial feeding area closed in 1971. There was also a fish hatchery in Yosemite Valley, from 1927 to 1956, where bears once helped themselves to fresh trout from the holding tanks. But closing the hatchery and the feeding areas didn’t stop bears from eating human food.

“The bears just went back to the campgrounds and hotels and continued to find human food,” Hopkins said.

The average figures for the proportion of human food in bear diets during the four time periods in the study were 13 percent for the period from 1915 to 1919; 27 percent for 1928 to 1939; 35 percent for 1975 to 1985; and 13 percent again for 2001 to 2007.

These results are based on a kind of chemical forensics in which Koch’s lab specializes. Isotopic analysis of an animal’s tissues can yield clues to its diet because of natural variability in the abundance of rare isotopes of elements such as carbon and nitrogen. Isotope ratios (the ratio of carbon-13 to carbon-12, for example) are different in human foods than in the wild plants and animals that black bears naturally eat in Yosemite, partly due to the large amounts of meat and corn-based foods in our diets.

In order to analyze the data from Yosemite bears that ate a mixture of human and natural foods, Hopkins had to get samples from bears that did not eat any human food, and he had to track down samples of the non-native trout that had been raised in the hatchery. He also needed data representing a 100 percent human food diet, for which he turned to the Smithsonian Institution for samples of human hair from different periods over the past century.

“He searched far and wide to get the collection of samples we analyzed, and that collection made the study powerful enough to answer the question of how management practices affect bear diets,” Koch said.

According to Hopkins, the key to managing bear problems is to prevent bears from becoming conditioned to eat human food in the first place.