Isegoria

How do big whales manage to put enough tiny bits of food in their bodies to get to such huge sizes?

For example, a fin whale will dive hundreds of feet down in search of food. Once it gets deep enough, it speeds up dramatically, and then abruptly slows down, almost stopping. Yet even as it slows, its tail is still moving up and down, generating tremendous thrust. Then, about half a minute later, it speeds up and slows down again. What’s going on?

According to the scientists, this pattern occurs when the whales lunge into a cloud of krill and drop open their jaws. Pleats under the lower jaw open up, engulfing huge amounts of water. The whale slows down because of the drag. It behaves, in other words, a lot like a parachute.
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It’s a lot of water, the scientists have found: in one lunge, a fin whale can momentarily double its weight.

If a whale simply let the water come rushing in, there would be a tremendous collision — more than a whale could handle. Instead, the scientists argue, the whales actively cradle their titanic gulp. As the water rushes in, the whales contract muscles in their lower jaw. The water slows down and then reverses direction, so that it’s moving with the whale. (It just so happens that fin whales do have sheets of muscle and pressure-sensinging nerve endings in their lower jaw. Before now, nobody quite knew before what they were for.) Once the water is moving forward inside the whale it can then close its mouth and give an extra squeeze to filter the water through its baleen.

This bizarre strategy may be the secret to the huge size of some whales. A fin whale can get 20 pounds of krill in a single gulp, but it can gulp every 30 seconds. Because krill live in gigantic swarms, they can keep gulping and get enough food in four hours to fuel their bodies for an entire day.

Big fin whales are not just scaled-up versions of little fin whales:

Instead, as their bodies get bigger, their mouths get much bigger. Small fin whales can swallow up about 90% of their own body weight. Very big ones can gulp 160%. In other words, big fin whales need more and more energy to handle the bigger slugs of water they gulp. As their body increases in size, the energy their bodies demand rises faster than the extra energy they can get from their food.

Researchers are once again taking seriously the notion of smart dogs:

Their apparent ability to tune in to the needs of psychiatric patients, turning on lights for trauma victims afraid of the dark, reminding their owners to take medication and interrupting behaviors like suicide attempts and self-mutilation, for example, has lately attracted the attention of researchers.

In September, the Army announced that it would spend $300,000 to study the impact of pairing psychiatric service dogs like Jet with soldiers returning from Iraq and Afghanistan with post-traumatic stress disorder. Both the House and Senate have recently passed bills that would finance the training and placement of these dogs with veterans.

Hungarian researchers reported in a study last year that a guide dog for a blind and epileptic person became anxious before its master suffered a seizure and was taught to bark and lick the owner’s face and upper arm when it detected an onset, three to five minutes before the seizure. It is still somewhat mysterious how exactly dogs detect seizures, whether it’s by picking up on behavioral changes or smelling something awry, but several small studies have shown that a powerful sense of smell can detect lung and other types of cancer, as the dogs sniff out odors emitted by the disease.

Dogs can understand language and perform other “human” cognitive tasks much better than scientists used to accept:

By giving dogs language learning and other tests devised for infants and toddlers, Dr. Coren has come up with an intelligence ranking of 100 breeds, with border collies at No. 1. He says the most intelligent breeds (poodles, retrievers, Labradors and shepherds) can learn as many as 250 words, signs and signals, while the others can learn 165. The average dog is about as intellectually advanced as a 2- to 2-and-a-half-year-old child, he has concluded, with an ability to understand some abstract concepts. For example, the animal can get “the idea of being a dog” by differentiating photographs with dogs in them from photographs without dogs.

Steve Sailer adds an interesting meta-point about such articles:

Something I’ve noticed over the years in this kind of article or television documentary about all the new tasks to which dogs are being applied is that they seldom mention what would have immediately occurred to a pre-20th Century reader. Contemporary readers are interested in the selection process for finding dogs with the best propensities for the job and the subsequent training process. But a 19th Century reader would have immediately thought of taking the dogs who are best at a particular skill and breeding them together.

Consider the Newfoundland, a giant water dog with webbed feet who doesn’t dog paddle like the average dog, but uses a more powerful technique rather like the breast stroke. Moreover, Newfoundlands desperately want to rescue people from drowning. On shorelines all over the world, there are statues of heroic Newfoundlands who rescued humans from watery graves. Unfortunately, you can’t really take a Newfoundland for a walk along a public beach because he might immediately splash into the water and start hauling protesting swimmers out.

Presumably, it took a lot of generations of selective breeding to come up with a great beast with these characteristics. Presumably, you could breed together dogs that are best at each new job and eventually come up with new breeds where a much higher percentage of the dogs would pass the selection process and would require less training. But modern readers don’t want to hear about that because that would be eugenics. For example, here’s Jonah Goldberg’s 2002 National Review Online column:

Westminster Eugenics Show
Repugnant thinking that’s died out for humans is thriving at the Westminster Kennel Club.

This is not to say that foresighted individuals aren’t developing new breeds, just that the entire concept is usually left out of mainstream discussions.

For example, I’ve seen it claimed that a few dogs can sniff out cancer in people, at least melanomas on the skin. I don’t know how accurate that is, but say you could develop over a few decades a breed of dog that could detect a variety of cancers by sniffing people. Think of what a boon that would be to the world’s poor — instead of expensive scans, doctors in poor places could do cancer screenings for the price of dog food!

But this kind of thinking is unpopular today because the conventional wisdom is that eugenics is a “pseudoscience” — i.e., it’s not just morally wrong, it’s impossible.

The more we study dolphins, the brighter they turn out to be:

At the Institute for Marine Mammal Studies in Mississippi, Kelly the dolphin has built up quite a reputation. All the dolphins at the institute are trained to hold onto any litter that falls into their pools until they see a trainer, when they can trade the litter for fish. In this way, the dolphins help to keep their pools clean.

Kelly has taken this task one step further. When people drop paper into the water she hides it under a rock at the bottom of the pool. The next time a trainer passes, she goes down to the rock and tears off a piece of paper to give to the trainer. After a fish reward, she goes back down, tears off another piece of paper, gets another fish, and so on. This behaviour is interesting because it shows that Kelly has a sense of the future and delays gratification. She has realised that a big piece of paper gets the same reward as a small piece and so delivers only small pieces to keep the extra food coming. She has, in effect, trained the humans.

Her cunning has not stopped there. One day, when a gull flew into her pool, she grabbed it, waited for the trainers and then gave it to them. It was a large bird and so the trainers gave her lots of fish. This seemed to give Kelly a new idea. The next time she was fed, instead of eating the last fish, she took it to the bottom of the pool and hid it under the rock where she had been hiding the paper. When no trainers were present, she brought the fish to the surface and used it to lure the gulls, which she would catch to get even more fish. After mastering this lucrative strategy, she taught her calf, who taught other calves, and so gull-baiting has become a hot game among the dolphins.

They show plenty of intelligence in the wild too:

In an estuary off the coast of Brazil, tucuxi dolphins are regularly seen capturing fish by “tail whacking”. They flick a fish up to 9 metres with their tail flukes and then pick the stunned prey from the water surface. Peale’s dolphins in the Straits of Magellan off Patagonia forage in kelp beds, use the seaweed to disguise their approach and cut off the fishes’ escape route. In Galveston Bay, Texas, certain female bottlenose dolphins and their young follow shrimp boats. The dolphins swim into the shrimp nets to take live fish and then wriggle out again — a skill requiring expertise to avoid entanglement in the fishing nets.

Dolphins can also use tools to solve problems. Scientists have observed a dolphin coaxing a reluctant moray eel out of its crevice by killing a scorpion fish and using its spiny body to poke at the eel. Off the western coast of Australia, bottlenose dolphins place sponges over their snouts, which protects them from the spines of stonefish and stingrays as they forage over shallow seabeds.
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In the shallows of Florida Bay, Laura Engleby and her team have recently discovered an ingenious fishing strategy. A number of the local dolphin groups seem to use a circle of mud to catch mullet. The action usually begins with one dolphin swimming off in a burst of speed. It then dives below the surface, circling a shoal of fish, stirring up mud along the way. On cue, the other dolphins in the group move into position, forming a barrier to block off any underwater escape routes. As the circle of mud rises to the surface, the mullet are trapped. Their only option is to leap clear out of the water and unwittingly straight into the open mouths of the waiting dolphins.

They can mimic people:

At a dolphinarium, a person standing by the pool’s window noticed that a dolphin calf was watching him. When he released a puff of smoke from his cigarette, the dolphin immediately swam off to her mother, returned and released a mouthful of milk, causing a similar effect to the cigarette smoke. Another dolphin mimicked the scraping of the pool’s observation window by a diver, even copying the sound of the air-demand valve of the scuba gear while releasing a stream of bubbles from his blowhole.

They don’t seem to have a true language — but they can learn to understand human-created languages:

At Kewalo Basin Marine Laboratory in Hawaii, Lou Herman and his team set about testing a dolphin’s ability to comprehend our language. They developed a sign language to communicate with the dolphins, and the results were remarkable. Not only do the dolphins understand the meaning of individual words, they also understand the significance of word order in a sentence. (One of their star dolphins, Akeakamai, has learned a vocabulary of more than 60 words and can understand more than 2,000 sentences.) Particularly impressive is the dolphins’ relaxed attitude when new sentences are introduced. For example, the dolphins generally responded correctly to “touch the frisbee with your tail and then jump over it”. This has the characteristics of true understanding, not rigid training.

And they seem self-aware:

Diana Reiss and her researchers installed mirrors inside New York Aquarium to test whether two bottlenose dolphins were self-aware enough to recognise their reflections. They placed markings in non-toxic black ink on various places of the dolphins’ bodies. The dolphins swam to the mirror and exposed the black mark to check it out. They spent more time in front of the mirror after being marked than when they were not marked. The ability to recognise themselves in the mirror suggests self-awareness, a quality previously only seen in people and great apes.

Not only do dolphins recognise their mirror images, but they can also watch TV. Language-trained chimps only learned to respond appropriately to TV screens after a long period of training. In contrast, Lou Herman’s dolphins responded appropriately the very first time they were exposed to television.

Naked mole rats are ugly little creatures, but they’re ugly little creatures that don’t get cancer:

Despite a 30-year lifespan that gives ample time for cells to grow cancerous, a small rodent species called a naked mole rat has never been found with tumors of any kind — and now biologists at the University of Rochester think they know why.

The findings, presented in today’s issue of the Proceedings of the National Academy of Sciences, show that the mole rat’s cells express a gene called p16 that makes the cells “claustrophobic,” stopping the cells’ proliferation when too many of them crowd together, cutting off runaway growth before it can start. The effect of p16 is so pronounced that when researchers mutated the cells to induce a tumor, the cells’ growth barely changed, whereas regular mouse cells became fully cancerous.
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Like many animals, including humans, the mole rats have a gene called p27 that prevents cellular overcrowding, but the mole rats use another, earlier defense in gene p16. Cancer cells tend to find ways around p27, but mole rats have a double barrier that a cell must overcome before it can grow uncontrollably.

Haast’s eagle, a 40-pound bird that lived in New Zealand until 500 years ago, was a predator and not simply a scavenger, according to Ken Ashwell of the University of New South Wales in Australia and Paul Scofield of the Canterbury Museum — and Maori folklore:

Using computed axial tomography, or CAT, the researchers scanned several skulls, a pelvis and a beak in an effort to reconstruct the size of the bird’s brain, eyes, ears and spinal cord.

They compared their data on the Haast’s eagle to characteristics of modern predator birds and scavenger birds to determine that the bird was a fearsome predator that ate the flightless moa birds and even humans.

The researchers also determined the eagle quickly evolved from a much smaller ancestor, with the body growing much more quickly than the brain. They believe its body grew 10 times bigger during the early to middle Pleistocene period, 700,000 to 1.8 million years ago.

“This work is a great example of how rapidly evolving medical techniques and equipment can be used to solve ancient medical mysteries,” Ashwell said.
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Scientists believe the Haast’s eagle became extinct about 500 years ago, most likely due to habitat destruction and the extinction of its prey species at the hands of early Polynesian settlers. Before the humans colonized New Zealand about 750 years ago, the largest inhabitants were birds like the Haast’s eagle and the moa.

Scofield said the findings are similar to what he found in Maori folk tales. “The science supports Maori mythology of the legendary pouakai or hokioi, a huge bird that could swoop down on people in the mountains and was capable of killing a small child,” he said.

Biologists from Oxford University, the London Zoo, and the Smithsonian Institution have discovered a lost world in Papua New Guinea‘s Bosavi crater:

A team of scientists from Britain, the United States and Papua New Guinea found more than 40 previously unidentified species when they climbed into the kilometre-deep crater of Mount Bosavi and explored a pristine jungle habitat teeming with life that has evolved in isolation since the volcano last erupted 200,000 years ago. In a remarkably rich haul from just five weeks of exploration, the biologists discovered 16 frogs which have never before been recorded by science, at least three new fish, a new bat and a giant rat, which may turn out to be the biggest in the world.
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They found the three-kilometre wide crater populated by spectacular birds of paradise and in the absence of big cats and monkeys, which are found in the remote jungles of the Amazon and Sumatra, the main predators are giant monitor lizards while kangaroos have evolved to live in trees. New species include a camouflaged gecko, a fanged frog and a fish called the Henamo grunter, named because it makes grunting noises from its swim bladder.

View the photo gallery.

A study, published in Current Biology, shows that crows are innovative tool users — and the Times has video of a bird playing out one of Aesop’s fables:

As the 2000-year-old story goes, the crow filled the bucket of water with stones until the level became high enough for him to quench his thirst.

Just a fable? Apparently not. Footage shows a rook — a relation of the crow — performing the feat to reach a worm floating on the water’s surface.

Malaria jumped to humans from chimpanzees at some point in the last two million years:

After gathering blood samples from nearly 100 chimpanzees in central Africa, researchers uncovered eight new strains of the parasite that causes chimp malaria. By comparing genes from the new chimp strains to genes from human malaria, scientists discovered that like HIV, our malaria bug is a gift from chimpanzees.

“The conventional wisdom on malaria is that this is a disease that has been in humans since the dawn of humanity,” said infectious disease expert Nathan Wolfe of Stanford University, who co-authored the paper published Monday in the Proceedings of the National Academy of Sciences. “In fact, what we found was really quite surprising to us: There is a tremendous diversity of these parasites in chimpanzees, and it’s a diversity that completely encompasses a much more limited diversity in human malaria.”

“There’s only one way to interpret that finding,” Wolfe said. “Namely, that this is a chimpanzee parasite that had jumped over to human populations.”
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The researchers think chimpanzee malaria was probably carried to humans by mosquitoes. And although the main transmission event happened only once, Wolfe thinks that in some remote areas, there could be an ongoing exchange of parasites between humans and chimps.

Clearly then our only course of action is to exterminate all chimps — in self-defense. Right?

Karen McComb of the University of Sussex and her team recorded the purrs of 10 different cats when they were soliciting food, and when they were purring in a different context — and they found that hungry cats mimic a baby’s cry:

Fifty people who were asked to rate the purrs on how pleasant and urgent they sounded consistently rated the “solicitation purrs” as more urgent and less pleasant. Cat owners were especially good at distinguishing between the two kinds of purring.

When the team examined the sound spectrum of the solicitation purrs they saw an unusual peak in the 220 to 520-hertz frequency range embedded in the much lower frequencies of the usual purr. Babies’ cries have a similar frequency range, 300 to 600 hertz, McComb says.

Salamanders can regrow amputated limbs, and they can grow them back so well that it’s hard to tell they were ever injured — which is why scientists have been studying salamander limb regeneration:

In salamanders, new tissues come from a tumorlike mass of cells that forms at the site of the injury, called the blastema. Until now, most scientists thought that the blastema contained a population of stem cells that had become pluripotent — capable of giving rise to all the needed tissues. But a new paper in the journal Nature provides evidence that this is not the case. Instead, stem cells involved in regeneration only create cells of the tissue that they came from. The finding suggests that regeneration does not require cells to reprogram themselves as dramatically as scientists had assumed.

Previous studies relied on imperfect methods of tracking cells, like fluorescent dyes that may have leaked out to other cells:

In the latest study, Tanaka’s team employed a novel method for tracking the fate of cells from different tissues in a type of salamander called the axolotl. The researchers first created transgenic axolotls that carried green fluorescent protein (GFP) in their entire bodies. When the animals were still embryos, the researchers removed a piece of tissue from the limb region of the transgenic animals and transplanted the tissue into the same location in nontransgenic axolotls. The transplants were incorporated into the growing body as normal cells, and when the limb of the transplant recipients were then severed, the researchers could track the fate of the fluorescent cells as the limb regrew.

The researchers used this method to track the fate of cells of the inner and outer skin, muscles, and cartilage, as well as Shwann cells, which insulate nerve fibers. They found that, contrary to previous evidence, muscle cells at the amputation site only become muscle cells in the new limb. Other cell types also stuck to their previous identities; the only exception, Tanaka says, is that cells of the inner layers of skin and cartilage seem to be able to transform into one another. But for the most part, she says, the blastema is not a homogeneous mass of cells but “a mix of stem or progenitor cells from different tissues that stay separate during the whole process.”

Billions of Argentine ants around the world all actually belong to one single global mega-colony:

Argentine ants (Linepithema humile) were once native to South America. But people have unintentionally introduced the ants to all continents except Antarctica.

These introduced Argentine ants are renowned for forming large colonies, and for becoming a significant pest, attacking native animals and crops.

In Europe, one vast colony of Argentine ants is thought to stretch for 6,000km (3,700 miles) along the Mediterranean coast, while another in the US, known as the ‘Californian large’, extends over 900km (560 miles) along the coast of California. A third huge colony exists on the west coast of Japan.

While ants are usually highly territorial, those living within each super-colony are tolerant of one another, even if they live tens or hundreds of kilometres apart. Each super-colony, however, was thought to be quite distinct.

But it now appears that billions of Argentine ants around the world all actually belong to one single global mega-colony.
Researchers in Japan and Spain led by Eiriki Sunamura of the University of Tokyo found that Argentine ants living in Europe, Japan and California shared a strikingly similar chemical profile of hydrocarbons on their cuticles.

But further experiments revealed the true extent of the insects’ global ambition.

The team selected wild ants from the main European super-colony, from another smaller one called the Catalonian super-colony which lives on the Iberian coast, the Californian super-colony and from the super-colony in west Japan, as well as another in Kobe, Japan.

They then matched up the ants in a series of one-on-one tests to see how aggressive individuals from different colonies would be to one another.
Ants from the smaller super-colonies were always aggressive to one another. So ants from the west coast of Japan fought their rivals from Kobe, while ants from the European super-colony didn’t get on with those from the Iberian colony.

But whenever ants from the main European and Californian super-colonies and those from the largest colony in Japan came into contact, they acted as if they were old friends.

I for one welcome our new insect overlords.