How to tell if an object died 250 million years ago hibernated while alive?
However, sleep deprivation – a condition in which your metabolism is low – is a good strategy to do through a long and difficult winter when food can be scarce. Biologists will not be surprised that this change was discovered early in life history. But discovering convincing evidence of that is difficult.
Christian A. Sidor, professor of biology at the University of Washington and director of spinal biology at the Burke Museum in Seattle. And that only tells you where the animal died. It doesn't even tell you where the animal lived. ”
But Dr. Sidor and Megan R. Whitney, a former university graduate and now a Harvard researcher, believe they have good evidence of hibernation behavior in animals that lived in Antarctica a quarter of a billion years ago – before age & # 39; and dinosaurs.
This was a tumultuous time in the life of the entire planet, recovering from the largest extinction ever experienced on Earth, marking the end of the Permian geographical period and the beginning of the Triassic. Antarctica, then as it is now, was close to the South Pole, and may have presented some of the shelter found in the disaster, often called the Great Death. (The reason for the abolition is still debated.)
Dr. Whitney said the animal, Lystrosaurus, is about the size of a medium-sized dog with pigeon eyes and two small feathers, and is one of the species that has undergone mass extinction.
"It's an extraordinary animal," she said. “It's kind of a sausage. She had no teeth except for the two foreheads. ”
Although its name sounds like an animal – the Greek "lizard shovel" – this creature was very close to the animal.
Flavors – only a few inches, which may be used to dig roots and tubers to eat – are given indications that Lystrosaurus metabolism is slowing down.
Like modern elephants, the lizard Lystrosaurus has grown steadily. Thus, the cutting of a thin part of the forearm gave the record of the life of the animal, very similar to that of a tree, with a circular cycle of darkness and light. Dr. Whitney and Drs. Sidor compared the focal lengths of a list of six Lystrosaurus living in Antarctica and four from South Africa.
Antarctic ribs included close, thick-walled differences – most of the time when booming growth slowed, perhaps stopped, due to anxiety – while those in South Africa did not.
Although all the lands at that time were annexed by Pangea, the section now known as & # 39; Antarctica & # 39; it is still close to the Pole of the South and the present part of South Africa is still hundreds of miles north.
Temperatures are hotter then, so Antarctica is not covered with ice sheets. But The ground tends to be as it is now, which would lead to shorter days during the winter. Dark days they would slow the growth of plants, with only a few looga discount for the food and herbs as Lystrosaurus eat.
This is how the researchers interpreted the thickness of the darkness, the darkness resulting from the changes resembling waves. The shapes are similar to what is seen in the teeth of modern mammals that sleep in the winter.
The results also suggest that Lystrosaurus was warm-blooded. Although cold-blooded metabolism can often completely shut down, mammals at bedtime wake up periodically.
The results were published Thursday Journal of Communication Biology.
"The idea they are saying, OK, and there is really an interesting variation in the size of these traits tells us the history of animal life," said Kenneth Angielczyk, an expert in paleomammalogy & # 39; at the Field Museum of Natural History in Chicago. "That's something new and very exciting."
Dr. Angielczyk is not involved in Lystrosaurus research, although he is collaborating with other projects. Sidor and Dr. Whitney.
Whether Lystrosaurus really works or otherwise slows down metabolism biologists refer to it as a torpor – it can never be detected.
"This is the first study of its kind," said Drs. Whitney, "then it will be an introduction."