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The sloth’s popular image as a lazy creature that sleeps for most of the day has been called into question.

Rather than snoozing for more than 16 hours a day, as observed in captivity, sloths in the wild doze for less than 10 hours, research suggests.

Scientists caught sloths living in the rainforest of Panama and fitted them with a device that monitors sleep.

The findings, published in a Royal Society journal, may help shed light on human sleep disorders, they say.

Lead researcher Niels Rattenborg, of the Max Planck Institute for Ornithology in Starnberg, Germany, said the study demonstrated for the first time that it was possible to record sleep in a wild animal.

“The real exciting finding was that they only slept 9.6 hours a day, which is much less than what people popularly believed and less than had been observed in a previous study of sloths in captivity,” he told BBC News.

“So they still may be sloth-like in terms of their speed of movement but in terms of their sleep they don’t seem to sleep an inordinate amount of time.”

The work, published in the Royal Society journal Biology Letters, attempts to find traits that predict whether an animal sleeps more or less than another species. This might provide clues to the function of sleep, said Dr Rattenborg.

He added: “I think this finding is really going to open the door to a whole new age of sleep research on animals sleeping in their natural habitat.”

Proof of principle

Animals vary in the amount of sleep they need. Pythons, for example, sleep for 18 hours a day, while giraffes survive on just two hours.

To investigate sleeping patterns in wild sloths, the scientists, from Germany, Switzerland and the US, developed a small machine capable of monitoring brain patterns associated with sleep.

They caught three female brown-throated three-toed sloths living in rainforest near the Smithsonian Tropical Research Institute on Barro Colorado Island, Panama.

The animals were fitted with the data recorder and then released.

When re-captured several days later, measurements showed that they slept for an average of 9.6 hours a day, compared with a sleep time of 16 hours a day reported in sloths kept in captivity.

Dr Neil Stanley, an expert in sleep disorders at the Norfolk and Norwich University Hospital, UK, said animals tended to sleep much more in captivity, where they have all their needs met.

“It’s intuitive that animals would sleep less in the wild than in captivity - this technology gives us the opportunity to prove that’s true,” he said.

Despite many years of research into the function of sleep, there are still many unresolved questions.

It is known that sleep plays an important role in maintaining normal mental functions, but the precise mechanisms are unclear.

How to keep the lights on when all is still and the local windmill won’t budge? A small Norwegian island testing a way to store wind-generated energy for calm days may have found the answer.

The tiny, windswept island of Utsira, situated off Norway’s southwestern coast, is home to what is said to be the world’s first full-scale system for cleanly transforming surplus wind power into hydrogen.

Perched atop a 40-metre-high wind turbine on a perfectly windstill day, technician Inge Linghammer explains that at times like this or on days when the gales whipping the unsheltered island get too strong the windmill shuts down and stops pumping out power.

“You need to have back-up power when this happens,” he says, nodding towards the motionless blades.

On a good day, the island’s two wind turbines, planted on a small hill overlooking several red-painted wooden houses, produce more energy than the 210 people living here can use.

When they are down however, most of Utsira, which measures only six square kilometres, is furnished with electricity from the mainland.

But 10 households receive clean, wind-generated electricity regardless of the weather conditions, thanks to a pilot project launched here in July, 2004 making it possible to store wind power by transforming it into hydrogen.

Surplus wind-generated energy is passed through water and, using electrolysis, the hydrogen atoms are separated from the oxygen atoms that make up water molecules.

The hydrogen is then compressed and stored in a container that can hold enough hydrogen gas to cover the energy needs of the 10 households for two windless days.

“Utsira has more than enough wind power to be self-sustained … but the problem arises on a day like today when there is not enough wind,” explains Halgeir Oeya, who heads up the hydrogen technology unit at Norwegian energy giant StatoilHydro, which is running the project.

“This system allows us to deliver power with expected quality and reliability,” he says, standing next to the large metal electrolyser box baking in the spring sun.

Combining renewable energy and hydrogen, he says, makes most sense in secluded areas like the numerous islands lining the European coast or in remote Australian communities, which until now have been heavily dependent on carbon dioxide-spewing diesel fuel provided by a constant flow of truck convoys.

Islands like Utsira have long been considered ideal laboratories for renewable energy due to their total dependence on outside energy supplies and their access to powerful wind energy.

Oeya boasts that the people participating in the Utsira test project have no restrictions on how they use power, switching on the lights, dishwashers, television sets and stereos without a thought to how the wind is blowing.

And amid growing alarm over greenhouse gas-promoted global warming, they can do so with a clean conscience, he says, pointing out that “the only emission is oxygen.”

Producing and storing energy this way however is still, nearly four years after testing began, far more expensive than the hydraulic power produced on Norway’s mainland.

StatoilHydro has no intention of building up the system to compete with large-scale energy production, but even making it competitive in the small, remote communities far off the grid that make up its target market remains years off.

“This is not a commercial project as it stands,” Oeya acknowledges.

“We must have a bigger scale in order to compete … and this will take a number of years,” he says.

Utsira mayor Jarle Nilsen is nonetheless ecstatic about the system and its effects on his small island community.

“This is a fantastic project that has been good for Utsira,” he says, pointing out that initial concerns about noise levels and birds getting caught in the turbines had been laid to rest.

“We haven’t found a single dead bird,” he says.

Most importantly, the system was helping nudge his Utsira towards its goal of zero emissions within the next decade and had become a major tourist attraction.

“The tourists go over to the lighthouse first, but then they go to look at our windmills. They want to see the world’s first full scale wind and hydrogen project in action,” he says proudly.

Scraps of protein from the bones of a 68 million-year-old dinosaur and a mastodon carcass confirm their places in the family tree of life on Earth, researchers reported on Thursday.

The same team that established Tyrannosaurus rex is a distant relative of chickens filled in more gaps, showing that the dinosaur was far more closely related to living birds than to alligators.

And a 500,000-year-old mastodon is clearly a close relative of elephants, John Asara and colleagues at Beth Israel Deaconess Medical Center and Harvard Medical School in Boston reported.

They said their analysis of the ancient preserved proteins can be used to fill in all sorts of gaps in the tree of evolution. But it also shows that classical methods, based on studying an animal’s bones and other physical structures, are accurate.

“If you … just use molecular data, you can come to the same conclusion,” Asara said in a telephone interview.

Asara’s team used collagen taken from a remarkable find — the leg bone of a T. rex sealed in stone and broken when researchers had no other way of removing it.

Mary Schweitzer of North Carolina State University was able to get soft tissue and then protein out of the bone in 2005 — something previously considered impossible. She also got protein out of the much younger mastodon bone.

Asara’s team looked at the protein on a molecular level and designed a computer program to analyze it. A year ago, they established that the Tyrannosaurus was related to modern chickens and ostriches and that the mastodon was related to living mammals.

T. REX AND BIRDS

Now, reporting in the journal Science, they said they have established that the dinosaur is more similar to birds than to alligators or other reptiles such as anole lizards.

“Last year we just made a very loose connection based on (protein) sequence identification and we had no reptiles,” Asara said. “And now with very high probability we can make the connection of T. rex to birds.”

The mastodon “groups very nicely with elephants,” he said. “We can get a very nice tree.”

Some of the computer programs take days to run, Asara noted. But they will keep seeking fresh samples from paleontologists.

“You can’t just grab things from museums,” Asara said, because the protein in them will have degraded.

Last September, a researcher at Pennsylvania State University reported his team had pulled DNA from the hair shafts of Siberian woolly mammoths that were 50,000 years old.

Separately on Thursday, scientists at the University of California, Berkeley said they had used new rock dating methods to pinpoint the extinction of the dinosaurs more precisely than ever before.

Their improved argon-argon dating method places the Cretaceous-Tertiary, or K/T, boundary at 65.95 million years ago, give or take 40,000 years. Earlier estimates had put it at 65.5 million years ago, with a 300,000-year margin of error.