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PARIS (AFP) – Tyrannosaurus Rex could sniff out distant prey even at night, yet another reason the flesh-ripping predator reigned supreme as king of the dinosaurs, according to a study published on Wednesday.
Earlier research had shown that the towering T-rex could see better than an eagle and would have been able to run down the fastest of humans.
The new study now unveils a previously unheralded weapon in the fearsome theropod's arsenal: a dangerously keen sense of smell.
Any trace of the brains of dinosaurs, which roamed Earth for tens of millions of years up to the end of the Cretaceous Period 65 million years ago, has long since disappeared.
But a trio of scientists led by Darla Zelenitsky at the University of Calgary in Alberta, Canada found a novel way to gage the sniffing prowess of T-rex and a couple dozen other meat-eating dinosaurs and primitive birds.
By examining fossil skull bones, the researchers were able to measure the size of indentations made by olfactory bulbs, the part of the brain associated with the sense of smell.
"Living birds and mammals that rely heavily on smell to find meat have large olfactory bulbs," Zelenitisky said in a statement.
The same animals also tend to prowl for prey at night, and cover vast areas, he added.
Of all the dinosaurs examined, the T-rex had the largest olfactory bulb relative to its overall size.
The study, published in the British journal Proceedings of the Royal Society B, also found that primitive birds had high-performance odor detectors, challenging a long-held assumption about the evolution of winged vertebrates.
"It has been previously suggested that smell had become less important than eye sight in the ancestors of birds, but we have shown that this wasn't so," said Zelenitsky.
Archaeopteryx, for example, which took to the skies during the Jurassic Period some 150 million years ago, had a sense of smell comparable to meat-eating dinosaurs along with excellent eye sight, the study said.
Somewhere along the way birds began to lose their sense of smell, but the decline probably happened far later than previously thought, the study concludes.
TOKYO (AFP) – Japanese scientists said Tuesday they had created a mouse from a dead cell frozen for 16 years, taking a step in the long impossible dream of bringing back extinct animals such as mammoths.
Scientists at the government-backed research institute Riken used the dead cell of a mouse that had been preserved at minus 20 degrees Celsius (minus 4 degrees Fahrenheit) -- a temperature similar to frozen ground.
The scientists hope that the first-of-a-kind research will pave the way to restore extinct animals such as the mammoth.
The findings were published in the Proceedings of the National Academy of Sciences in the United States.
The scientists extracted a cell nucleus from an organ of the dead mouse and planted it into an egg of another mouse which was alive, leading to the birth of the cloned mouse, the researchers said.
"The newly developed technology of nucleus transfer greatly improved the possibility of reviving extinct animals," the research team led by Teruhiko Wakayama said in a statement.
"Even though reviving extinct animals is often described in films and novels -- such as in Michael Crichton's 'Jurassic Park' -- it had in reality been impossible," they said.
Cells from dead bodies have previously been useless as they are ruined in the freezing process. But Wakayama's team discovered a way to extract a nucleus intact from a frozen cell by grinding cell tissues into multiple pieces.
The cloned mouse was able to reproduce with a female mouse, it added.
But the researchers said tough challenges remain ahead in terms of how to restore extinct animals, which would require breeding with animals that are still alive.
To revive a mammoth, researchers would need to find a way to implant a cell nucleus of a mammoth into the egg of an elephant and then implant the embryo into an elephant's uterus, it said.
The elephant is the closest modern relative of the mammoth, a huge woolly mammal believed to have died out with the Ice Age.
But Akira Iritani, a mammoth expert at Kinki University in Osaka, said it was only a matter of time before researchers could find a mammoth for a resurrection project.
"I have high hopes that we will be able to find a fine sample," he told public broadcaster NHK.
"It's said that there are more than 10,000 mammoths lying underneath Siberia," he said.
Even if it is impossible to recreate a whole animal, the process could create cloned embryonic stem cells for extinct species, giving a boost to research on evolution and zoology, he said.
Cloning can be controversial in terms of both bioethics and, if the animals are eaten, food safety.
Earlier this year, a report by the European Union warned that cloning can threaten the health of livestock.
South Korea's parliament has passed a law to regulate research into cloning, following a scandal in which a now-disgraced expert falsely claimed to have made the first human clone stem cells.
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NEW YORK – This year's ozone hole over Antarctica was the fifth biggest on record, reaching a maximum area of 10.5 million square miles in September, NASA says. That's considered "moderately large," NASA atmospheric scientist Paul Newman said in a statement.
NASA has tracked the size of the hole for 30 years. Last year, it was 9.7 million square miles, about the size of North America.
The hole is an area of depletion in the stratospheric ozone layer, which blocks harmful ultraviolet rays from space. Created by human-produced gases, the ozone hole generally forms in August and grows to its maximum size in September or October before breaking up.
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PARIS (AFP) – Tyrannosaurus Rex could sniff out distant prey even at night, yet another reason the flesh-ripping predator reigned supreme as king of the dinosaurs, according to a study published on Wednesday.