Friday, 6 April 2012

The Secrets Of Ice Mammoths

The baby mammoth Lyuba
Mammoths are one of the most iconic prehistoric animals. They were around when our species evolved and are just within the bounds of human memory. Today their skeletons line the halls of natural history museums across the world.

When the first remains were uncovered in antiquity, they were thought to have belonged to giants. We now know of their true origins and how they are related to their modern day counterpart, the elephant.

In fact they are the only prehistoric creature whose life has been reconstructed almost in full. Yet these developments have been recent due to incredible discoveries from the Siberian permafrost. True fossils take millions of years to form. The bones of giant ice age mammals such as mammoths have undergone partial preservation, but not the mineralisation present in true fossils. The soft tissues will be almost gone but some will remain.

This is present in bones recovered from the ground or from more unusual locations such as the La Brea tar pits in California. On the other hand, the bones found in the Siberian permafrost have simply been halted in the passage of time. They are so well preserved that they are almost indistinguishable from bones found in archaeological sites. Some contain the marrow, while others record the growth rings which develop as the bones grow bigger.

Larger carcasses still have sections of skin and hair as well as internal organs with stomach contents. Perhaps the best example is the body of a young, one month old female recovered from the Arctic Yamal Peninsula, named Lyuba. The only part missing was the tail. It has given us incredible anatomical insight into the mammoth and its socialization in herds. Now a second baby mammoth has been found which shows just exactly how useful they were to humans.

The Mammuthus organisation exists to study and collect fossil remains as they are slowly brought to the surface by the melting ice. As Siberia is such a vast place, they rely on information and potential sightings reported by reindeer herders, native people and workers on various oil and mineralogical expeditions. Recently the organisation responded to a call reporting a skull in an ice cliff on the edge of Lake Bustakh in east Siberia

They found the skull was connected to a body, and they named the 10,000 year old mammoth Yuka.Yet there were a number of strange features, and the body was covered in lacerations. 'Already there is dramatic evidence of a life-and-death struggle between Yuka and some top predator, probably a lion' said Daniel Fisher, professor of earth and environmental sciences at the University of Michigan. 'Even more interesting, there are hints that humans may have taken over the kill at an early stage.'

Yuka the juvenile mammoth
By studying the bones and tusks, the researchers found that Yuka was two and a half years old when she was buried in the permafrost. Still very young, she would have been easily overpowered. One leg was broken, suggesting that she tried to flee.

No predator, however, removes all the bones from the inside by carving a long slit down the back without chewing through the skin. When creatures like lions chase down their prey, they usually grip onto the belly, neck or face.

Such marks were absent, but scallop-shaped grazes on the flanks has led the researchers to believe that early hunters chased the predators from their kill and used stone tools to remove the valuable resources from the carcass. Either way, the carcass was still beautifully complete. The strawberry blond hair still covered the skin and the foot-pads were present, albeit cracked from the extreme cold.

'These are remarkably rare finds and have huge significance. It will be a boon to researchers as it will help them link observed phenotypes (morphological features that we can see) with genotype (DNA sequences)' said Kevin Campbell, associate professor of environmental and evolutionary physiology at the University of Manitoba. As the Arctic ice continues to melt, it is likely that more and more finds will appear, providing us with more insight into the mammoth and its lifestyle.