Norwegian Lemmings

Sunday, December 14th, 2014

Norwegian LemmingNorwegian lemmings go through dramatic population cycles, with their density increasing and then decreasing by a factor of 3,000:

Accounts of lemming migrations go back hundreds of years. In 1823, for instance, one explorer wrote of seeing “such inconceivable numbers” in his Scandinavian travels “that the country is literally covered with them”.

An army of lemmings advanced with extraordinary purpose, “never suffering itself to be diverted from its course by any opposing obstacles,” not even when confronted by rivers, or even the branches of narrow fjords. “They are good at swimming,” says Stenseth. “They can easily go across small bodies of water, across small lakes,” he says.

Given such sudden and apparently reckless behaviour, it is perhaps inevitable that local people in bygone centuries came to see the lemming as a crazed creature, and a swarm as “the forerunner of war and disaster”. But we have Walt Disney to thank for really embedding this stereotype in the public consciousness.

On the back of the animated classic Bambi, Disney undertook a series of ground-breaking, feature-length nature documentaries known as The True-Life Adventures. In one of these, White Wilderness, he dramatised the lemming mass suicide.

Stenseth is generous about the movie. “It is a nice film actually,” he says. “But there are some bits and pieces that are wrong with it. That [the lemming segment] is one of them.”

For a start, White Wilderness – filmed in Canada rather than Scandinavia – depicts the wrong species. Although all lemmings experience population highs and lows, the accounts of mass movements were all based on observations of Norwegian lemmings, not the brown lemmings that Disney used. He paid Eskimos “$1 a live lemming,” says Stenseth.

But that’s just the start. In an infamous sequence, the lemmings reach the edge of a precipitous cliff, and the voiceover tells us that “this is the last chance to turn back, yet over they go, casting themselves bodily out into space.”

It certainly looks like suicide. “Only they didn’t march to the sea,” says Stenseth. “They were tipped into it from the truck.”

Once you know the sequence has been faked, it makes for rather awkward viewing.

That movie-fueled myth did lead to a delightful computer game though.

The Problem With Pit Bulls

Sunday, November 30th, 2014

The problem with pit bulls is that they simply aren’t just like other dogs:

Pit bulls make up only 6% of the dog population, but they’re responsible for 68% of dog attacks and 52% of dog-related deaths since 1982, according to research compiled by Merritt Clifton, editor of Animals 24-7, an animal-news organization that focuses on humane work and animal-cruelty prevention.

Clifton himself has been twice attacked by dogs (one pit bull), and part of his work involves logging fatal and disfiguring attacks. Clifton says that for the 32 years he’s been recording, there has never been a year when pit bulls have accounted for less than half of all attacks. A CDC report on dog-bite fatalities from 1978 to 1998 confirms that pit bulls are responsible for more deaths than any other breed, but the CDC no longer collects breed-specific information.

Another report published in the April 2011 issue of Annals of Surgery found that one person is killed by a pit bull every 14 days, two people are injured by a pit bull every day, and young children are especially at risk. The report concludes that “these breeds should be regulated in the same way in which other dangerous species, such as leopards, are regulated.” That report was shared with TIME by PETA, the world’s largest animal-rights organization.

Pit Bull Attacks

“If you need a marker in your head for when pit bulls got out of control, it’s 2007 with Michael Vick,” Lynn says. Vick’s high-profile trial for dogfighting and cruelty to animals roused a growing sympathy for pit bulls, which led more people to adopt them and bring them into their homes.

“We need to get used to mauling injuries, because we’re going to be seeing a lot more of them,” warns Lynn. “Each of us will know a mauled, disfigured child by a known dangerous breed of dog. There will be one in every school.”

But what can be done about the growing number of pit bulls? Some say the best solution would be breed-specific sterilization, which would curb the pit-bull population and reduce euthanasia in shelters. Most dogs of all breeds are spayed and neutered — about 80%, by Clifton’s estimation. But only 20% of pit bulls are sterilized, partly because the population that owns pit bulls tends to resist the spay-neuter message. He notes that there are a number of free sterilization programs for pit bulls, including one run by the ASPCA, but that even the largest programs aren’t sterilizing enough pit bulls to reduce the number of shelter intakes.

Lynn agrees that breed-specific sterilization laws are the most humane and efficient way to deal with the situation and avoid having more dogs euthanized. “If you want to hit that ‘no kill’ status, you better do something about the pit-bull problem.” Pit bulls currently account for 63% of the dogs put down in shelters, but only 38% of the admissions. Lynn says that all pit bulls should be sterilized, except those that come from licensed breeders.

Even PETA, the largest animal-rights organization in the world, supports breed-specific sterilization for pit bulls. “Pit bulls are a breed-specific problem, so it seems reasonable to target them,” said Daphna Nachminovitch, PETA’s senior vice president of cruelty investigations. “The public is misled to believe that pit bulls are like any other dog. And they just aren’t.” Even the ASPCA acknowledges on its website that pit bulls are genetically different than other dogs. “Pit bulls have been bred to behave differently during a fight,” it says. “They may not give warning before becoming aggressive, and they’re less likely to back down when clashing with an opponent.”

Farmed Bluefin

Wednesday, November 19th, 2014

The Japanese treasure the rich red meat of hon-maguro or true tuna:

At an auction in Tokyo, a single bluefin once sold for $1.5 million, or $3,000 a pound.

All this has put the wild Pacific bluefin tuna in a perilous state. Stocks today are less than one-fifth of their peak in the early 1960s, around the time Japanese industrial freezer ships began prowling the oceans, according to an estimate by an international governmental committee monitoring tuna fishing in the Pacific. The wild population is now estimated by that committee at 44,848 tons, or roughly nine million fish, down nearly 50% in the past decade.

[...]

Not long ago, full farming of tuna was considered impossible. Now the business is beginning to take off, as part of a broader revolution in aquaculture that is radically changing the world’s food supply.

[...]

With a decadeslong global consumption boom depleting natural fish populations of all kinds, demand is increasingly being met by farm-grown seafood. In 2012, farmed fish accounted for a record 42.2% of global output, compared with 13.4% in 1990 and 25.7% in 2000. A full 56% of global shrimp consumption now comes from farms, mostly in Southeast Asia and China. Oysters are started in hatcheries and then seeded in ocean beds. Atlantic salmon farming, which only started in earnest in the mid-1980s, now accounts for 99% of world-wide production — so much so that it has drawn criticism for polluting local water systems and spreading diseases to wild fish.

Until recently, the Pacific bluefin tuna defied this sort of domestication. The bluefin can weigh as much as 900 pounds and barrels through the seas at up to 30 miles an hour. Over a month, it may roam thousands of miles of the Pacific. The massive creature is also moody, easily disturbed by light, noise or subtle changes in the water temperature. It hurtles through the water in a straight line, making it prone to fatal collisions in captivity.

Lagoon and Spray

Sunday, November 9th, 2014

Until recently, hogs roamed in outdoor pens or fields, where their droppings fertilized crops, but now hog-farming has gone big, and not everything scales well:

Most of the farms that survived did so by going big—raising thousands of animals that spend their entire lives inside barns. Today, Duplin County, North Carolina, the top swine producer in the country, is home to 530 hog operations with a collective capacity of 2.35 million animals. According to a 2008 GAO estimate, hogs in five eastern North Carolina counties produced 15.5 million tons of manure in one year.

To handle all that waste, farmers in North Carolina use a standard practice called the lagoon and spray field system. They flush feces and urine from barns into open-air pits called lagoons, which turn the color of Pepto-Bismol when pink-colored bacteria colonize the waste. To keep the lagoons from overflowing, farmers spray liquid manure on their fields nearby.

The result, says Steve Wing, an epidemiologist at the University of North Carolina at Chapel Hill, is this: “The eastern part of North Carolina is covered with shit.”

Caw vs. Croak

Thursday, October 30th, 2014

Crows and ravens can be tricky to tell apart by sight, but their voices are much more distinctive:

Mesopredator Release

Monday, October 13th, 2014

Over the past 100 years, coyotes have taken over America:

They are native to the continent, and for most of their existence these rangy, yellow-eyed canids were largely restricted to the Great Plains and western deserts where they evolved. But after wolves and cougars were exterminated from most of the United States by the 1800s, coyotes took their place. Colonizing some areas at a rate of 720 square miles per year, coyotes now occupy — or “saturate,” as one scientist I spoke with described it — nearly the entire continent. (Long Island is a notable exception.) The animals are now the apex predators of the east. And they’re proving so resourceful that even the last stronghold — the urban core — represents an opportunity to flourish.

Coyotes may be the most driven carnivores to penetrate modern cities in recent years, but they’re hardly the only ones. Raccoons, foxes, and skunks have long been prolific urban residents. And now bobcats, cougars, even grizzly bears — predators that symbolize wilderness, who typically require a lot of space and a stable prey base, and defend their territories — are not just visiting but occupying areas that scientists used to consider impossible for their survival. Dozens of grizzlies now summer within the city limits of Anchorage. The most urban cougar ever, a male named P22, has been canvassing Los Angeles’ Griffith Park for more than two and a half years. Bobcats prowl the Hollywood Hills and saunter near skyscrapers in Dallas. And in New York City, a predator is returning that hasn’t been seen since Henry Hudson’s day — the fisher, a dachshund-sized member of the weasel family with a long, thick tail. This spring, a police officer named Lenart snapped the first NYC photo of one, skulking on a Bronx sidewalk at dawn.

Why are these large weasels flourishing in the east?

“We found support that eastern fishers are experiencing what’s known as mesopredator release,” says Kays. “That means they overlap with fewer predatory species than they used to. There are no cougars; there are no wolves.” Without many big competitors to fear, middle-sized predators, or mesopredators, are free to change their habits: they can hunt in a wider range of places or times. They can also pursue larger prey (for fishers, that means hefty snowshoe hares, porcupines, or deer roadkill) without getting beaten to it or bullied. Scientists suspect that mesopredator release is fueling coyotes’ incredible expansion as well.

Most intriguingly, LaPoint and Kays discovered that the bodies of eastern fishers are actually getting bigger over time. These carnivores seem to be evolving to better catch larger-bodied prey by becoming larger themselves. A big, well nourished fisher is more likely to survive in new, challenging environments. “They’re getting bigger where their populations are expanding,” says LaPoint, which the team documented by comparing hundreds of museum specimens collected from the 19th century to the present. That’s brisk, evolutionarily speaking. “Within a century, more or less,” he says. “It’s pretty crazy.”

The rub is that this “wilderness” species seems to be quickly adapting to our presence. In persecuting North America’s biggest carnivores, we may be encouraging medium-sized ones to spread directly into the areas we now live, and in some cases, actually evolve into bigger, more resourceful predators.

(Hat tip to T. Greer.)

Cats and Dogs

Monday, October 13th, 2014

Leopards in India have an interesting diet:

The researchers found that domestic dogs were by far the most common prey, making up 39 percent of the leopards’ diet (in terms of biomass). The remains of domestic cats were found in 15 percent of poop samples and accounted for 12 percent of the mass of leopards’ meals.

By comparison, livestock were a relatively small portion of the leopard diet. Domestic goats, for example, accounted for just 11 percent of the mass of the big cats’ meals, even though they were seven times more abundant than dogs in the study area.

All told, 87 percent of the leopards’ diet was made up of domestic animals, including both livestock and pets; this suggests the leopards, though considered wild, are completely dependent on human-related sources of food. The small portion of the wild animals in the leopards’ diet consisted of mostly rodents, as well as civets, monkeys, mongooses and birds.

Euharamiyida

Thursday, September 11th, 2014

New specimens place three species of Euharamiyida firmly within the class of Mammals — a long, long time ago:

Paleontologists have described three new small squirrel-like species that place a poorly understood Mesozoic group of animals firmly in the mammal family tree. The study, led by scientists at the American Museum of Natural History and the Chinese Academy of Sciences, supports the idea that mammals — an extremely diverse group that includes egg-laying monotremes such as the platypus, marsupials such as the opossum, and placentals like humans and whales — originated at least 208 million years ago in the late Triassic, much earlier than some previous research suggests.

The study is published today in the journal Nature.

“For decades, scientists have been debating whether the extinct group, called Haramiyida, belongs within or outside of Mammalia,” said co-author Jin Meng, a curator in the Museum’s Division of Paleontology. “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.”

The three new species — Shenshou lui, Xianshou linglong, and Xianshou songae — are described from six nearly complete 160-million-year-old fossils found in China. The animals, which researchers have placed in a new group, or clade, called Euharamiyida, likely looked similar to small squirrels. They weighed between 1 and 10 ounces and had tails and feet that indicate that they were tree dwellers.

Arboreal Mammals in a Jurassic Forest

“They were good climbers and probably spent more time than squirrels in trees,” Meng said. “Their hands and feet were adapted for holding branches, but not good for running on the ground.”

The members of Euharamiyida likely ate insects, nuts, and fruit with their “strange” teeth, which have many cusps, or raised points, on the crowns. Mammals are thought to evolve from a common ancestor that had three cusps; human molars can have up to five. But the newly discovered species had two parallel rows of cusps on each molar, with up to seven cusps on each side. How this complex tooth pattern evolved in relation to those of other mammals has puzzled scientist for many decades.

Despite unusual tooth patterning, the overall morphology, or physical characteristics, seen in the new haramiyidan fossils is mammalian. For example, the specimens show evidence of a typical mammalian middle ear, the area just inside the eardrum that turns vibrations in the air into ripples in the ear’s fluids. The middle ears of mammals are unique in that they have three bones, as evidenced in the new fossils.

However, the placement of the new species within Mammalia poses another issue: Based on the age of the Euharamiyida species and their kin, the divergence of mammals from reptiles had to have happened much earlier than some research has estimated. Instead of originating in the middle Jurassic (between 176 and 161 million years ago), mammals likely first appeared in the late Triassic (between 235 and 201 million years ago). This finding corresponds with some studies that used DNA data.

“What we’re showing here is very convincing that these animals are mammals, and that we need to turn back the clock for mammal divergence,” Meng said. “But even more importantly, these new fossils present a new suite of characters that might help us tell many more stories about ancient mammals.”

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: