December 30, 2011, 4:15 p.m.

For typical

city folk, there may be no creature more pedestrian than the pigeon, that ubiquitous gray denizen of the sidewalks. But the bird’s reputation

got a boost this month when psychologists at the University of Otago in Dunedin, New Zealand, announced that pigeons can count — a skill previously presumed to be unique to primates.

The finding, which was published in the journal Science, is forcing experts to reconsider the evolution of mathematical ability. Postdoctoral fellow and study leader Damian Scarf explained why in a conversation with The Times.

Why study pigeons?

Comparative psychologists study a range of animals to figure out the evolution of different abilities.

Pigeons are just perfect subjects. They’re really good experimental animals. They are really easy to train, they’re really diligent workers — and they are interesting because they’re not a mammal, so their brains and their evolution are different. They split from mammals about 300 million years ago.

This research gives u

s an idea of the basic neural machinery required for these numerical abilities. It shows that you don’t need a brain like a primate’s or a mammal’s to be able to form these abstract concepts.

How are bird brains different?

Primates have a layered cortex, but pigeons don’t. The way their brains are organized is very different. But it seems that everything we have they have — it’s just packaged in a different way.

How do you test a bird’s ability to understand a mathematical concept?

The pigeons respond on touch screens. Pictures come up on the screen, the pigeons peck at them, and the touch screen registers their response.

In this case, we had three images: One had one object in it, another had two objects, and the third had three objects. We trained the pigeons to peck the pictures in ascending order.

We gave them lots and lots of these sets, with different shapes and sizes of objects, basically just reinforcing the one-two-three rule. They got a reward every time they got a correct response — a hopper gave them a little basket of wheat that they could peck from.

We trained them for a long, long time. Then we tested them with tiers of images, with numbers that were outside of that range, to see if they could transfer that ascending rule to novel numbers such as four and five and six and seven. They were able to do that as well as monkeys were, which was really surprising.

How long did it take to train the pigeons?

It took about an hour a day, seven days a week, every day for a whole year.

Your study in Science reported that the bigger the difference between numbers shown during testing, the better the pigeons performed. Why is that important?

It’s significant because it basically shows us that their way of processing the stimulus is similar to how we would process it. If you tested humans, you’d get the same effect. You’d also get the same effect if you tested adults’ ability to order letters in the alphabet. The greater the distance between letters, the easier adults can tell you which one comes first.

Have researchers tried this out on many other animals?

No, it’s just been primates and pigeons. Psychologists Elizabeth Brannon and Herbert Terrace tested rhesus monkeys in 1998, and since then people have looked at baboons, Capuchin monkeys and, most recently, lemurs.

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INTEL SOURCE LINK: latimes.com

By Amina Khan, Los Angeles TimesJanuary 13, 2012, 4:29 p.m.

A giant tortoise species studied by Charles Darwin and believed to be extinct for more than 150 years may be alive and well, an ambitious genetic survey has revealed.

Blood sampling of more than 1,600 tortoises on the largest Galapagos island, Isabela, has revealed that about 84 of them had at least one purebred parent from a supposedly extinct species that once lived at the other end of the archipelago.

Researchers hope they can find these tortoises in the flesh on Isabela Island, breed them in captivity and then release them back onto Floreana Island, their native home.

The study, published in Tuesday’s edition of the journal Current Biology, may be the first rediscovery of an “extinct” species ever made through looking for genetic markers in hybrid offspring.

The giant tortoise, among the largest living reptiles on Earth, is an icon of the Galapagos Islands, which take their very name from the Spanish word for tortoise, galápago. The creatures are thought to have arrived on the volcanic islands about 2 million to 3 million years ago from the South American mainland.

Each tortoise species — some larger, with domed shells, and others smaller, with saddleback shells — was unique to a particular island or volcano, living and evolving in isolation from the others. The diversity of tortoise species Darwin saw during his 1835 visit to the Galapagos Islands partly inspired his theory of evolution.

“I never dreamed that islands, about 50 or 60 miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted,” Darwin wrote in “The Voyage of the Beagle,” first published in 1839.

But within just a few years of Darwin’s voyage, one of the tortoises — the saddleback Chelonoidis elephantopus, living on the southern Floreana Island — had already vanished.

Darwin himself never saw one alive. Whaling ships and pirates had long hunted the animals for food and oil; tortoises were handy supplies to keep on board, as they could be stowed in the hull for months — flipped on their backs so they couldn’t escape — without receiving food or water.

And humans introduced new threats on the islands. Rats from the ships preyed upon tortoise eggs; goats trampled them and devoured the islands’ vegetation. All tortoise species around the Galapagos Islands suffered from the onslaught; but perhaps none more than Chelonoidis elephantopus. By 1850, it was gone.

In recent years, however, scientists sampling a different species, Chelonoidis becki, came across a surprising discovery. Within this population of tortoises native to Wolf Volcano on Isabela Island, there were a handful bearing traces of Floreana tortoise DNA in their genomes. At some time in the past, it appeared, the Floreana tortoise had made it to — and mated on — Isabela.

Spurred on by this suggestion that the Floreana tortoise might still exist on Isabela, the researchers, led by population geneticist Ryan Garrick, who is now at the University of Mississippi in Oxford, decided to look more closely.

Garrick and colleagues took blood samples from 1,669 tortoises living on Wolf Volcano — about one-fifth of the tortoise population there — and ran them against a database of tortoise DNA.

The analysis showed that 84 of the tortoises had more than just traces of C. elephantopus within them: One of their parents was purebred C. elephantopus, a creature supposedly extinct for more than a century and a half.

Based on genetic analysis, the scientists estimate that about 38 C. elephantopus tortoises had parented these offspring on Wolf Volcano. And though many of those parents may not be alive today, some probably are. Thirty of the 84 hybrids Garrick and his co-workers found were less than 15 years old, and the creatures are thought to live for more than 100 years. Purebred parents are very likely still roaming the volcano.

It’s just a matter of finding them.

George Amato, director of the genomics program at the American Museum of Natural History in New York, called the results “very exciting.”

“To be honest with you, I can’t think of another example of this kind of work on endangered species that’s done such a detailed job of reconstructing this very interesting history,” Amato said.

The researchers have some thoughts on how the tortoises managed to get from one of the southernmost islands to the archipelago’s northwestern edge. Fast-moving whalers, or pirates looking to reduce their load while fighting or fleeing, may have hurriedly dumped the animals, taken along for food, at sea.

“These guys don’t swim, but they float like a wine cork in a bathtub,” Garrick said. “The prevailing current goes northwest in the ocean, making [Isabela] island the last place they would catch land before getting swept into the north Pacific.”

The search is now on for live, purebred C. elephantopus tortoises on Isabela. If they’re found, the researchers hope to start a breeding program in captivity to raise more of them and then bring them back to their native Floreana.

Tortoises are a very important part of an island’s ecosystem, Garrick said. They keep the prickly pear cactus in check by grazing on it and, by relieving themselves around other parts of the island, also act as the plant’s primary seed-dispersal method.

Even if the purebred tortoises don’t turn up, intensively breeding the most promising hybrids could be useful as well, Garrick added.

“This really comes down to not giving up on biodiversity conservation, even when things look grim,” he said.

INTEL SOURCE LINK: latimes.com

Like the Advanced Hypersonic Weapon, the Pentagon’s Falcon HTV-2 hypersonic plane is part of the Prompt Global Strike program (AFP Photo / Handout / Darpa)

The US Army has tested a hypersonic missile, which travels six times faster than the speed of sound. It is part of a larger plan to have the capability to strike any place on the planet within an hour.

The missile, called the Advanced Hypersonic Weapon (AHW), was launched from Hawaii on Thursday, the Pentagon reported. A rocket delivered it to suborbital altitude, after which the glider went for its target on the Marshall Islands, some 3,700 kilometers away.

It hit less than 30 minutes later, which means its speed was at least 7,400 kilometer per hour, or about Mach 6. An aircraft must be able to fly faster than Mach 5, to qualify as hypersonic.

A Mach number is used to describe the speed of an object or a fluid in comparison to the speed of sound in that medium. Mach 1 means the object travels at the same speed as sound. However the speed of sound may vary depending on such conditions as temperature and composition, so the speed expressed in Mach number is also variable. The now-retired Concorde supersonic passenger planes used to fly at a cruising speed of about Mach 2.

The test was aimed at gathering data on “aerodynamics, navigation, guidance and control, and thermal protection technologies,” the Pentagon said.

The AHW is one of several projects of the Prompt Global Strike program. It is aimed at developing several weapons which can be launched from American territory and reach their destinations within an hour.

On August 11 the US Air Force tested another hypersonic glider called the HTV-2. It is faster than the AHW, with speeds reaching 27,000 kilometer per hour. But unlike the Army’s vehicle, it does not work well – the test was aborted due to a technical failure.

The Soviet Union developed ramjet engines capable of hypersonic locomotion and even tested one design, which successfully reached Mach 5.7. The work was stalled by the collapse of the USSR, and no weapon using this technology was ever produced.

INTEL SOURCE LINK: RT.COM