Mammoths' migrations could lead to extinction for thousands of kilometers

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Mammoths' migrations could lead to extinction for thousands of kilometers
Mammoths' migrations could lead to extinction for thousands of kilometers
Anonim

Paleochemists have revealed an unusually rich history of migrations of ancient mammoths, which traveled thousands of kilometers from one habitat to another in different eras of their life. This feature could be the reason for their extinction, the press service of the University of Alaska said on Thursday, citing an article in the journal Science.

"It is difficult to say whether mammoths migrated every season, but our measurements show that they traveled long distances. The mammoth we studied managed to visit various regions of Alaska, which surprised us, given the huge area of ​​the state," said a researcher at the University of Alaska in Fairbanks (USA) Matthew Wooller, whose words are quoted by the press service of the university.

Mammoths were one of the largest representatives of the megafauna that inhabited Eurasia and North America during the last era of glaciation. Their number was quite high only 50 thousand years ago, but these proboscis animals quickly disappeared about 20-15 thousand years ago, when the glaciers began to retreat. The exact reasons for their extinction are still the subject of controversy among scientists.

Woeller and his colleagues tried to find an answer to this question using the methods of chemistry. For this, scientists prepared sections of the tusk of one of the last mammoths, which lived in Alaska about 17 thousand years ago. Paleochemists have studied their isotopic composition in detail in the hope of understanding how the daily life of these giants proceeded.

The fact is that the concentrations of various isotopes in tooth enamel and bone tissue reflect where their owner lived and what food they ate. In particular, the proportions of strontium and heavy oxygen-18 isotopes make it possible to determine the habitat of a person or animal, and the ratio of nitrogen-15 to carbon-13 atoms - what food he ate.

The chemical history of the life of a mammoth

Mammoth tusks grow throughout their life, which allows you to study the history of their migration and determine the diet, tracking how the isotopic composition of the enamel changes when moving from the base of the tusk to its tip. Guided by this idea, the scientists compared their measurements with a map of the distribution of strontium isotopes in the rocks of different regions of Alaska.

As it turned out, the mammoth they studied was a real traveler who traveled all over Alaska over the long years of his life. He was born in the western regions of the state, but he subsequently migrated to its central regions, located several thousand kilometers east of the present-day coast of North America.

The mammoth spent the last years of his life in the north of modern Alaska, in the vicinity of the Brooks Ridge, located above the Arctic Circle. What made him leave the southern regions, scientists cannot yet say, however, sharp shifts in the proportion of nitrogen-15 in different layers of tusk enamel testifies to the fact that the mammoth did not eat well in the last years of its life and died of hunger.

The reason for this, in turn, could be both climate change, which deprived mammoths of their usual food sources, and the fact that the male could be expelled from his herd, as is often the case in groups of modern elephants, and lost the chances of migration to other regions of Alaska. … Both of them led to the fact that the animal died from a chronic lack of calories in late winter or early spring.

Scientists hope that an isotope analysis of the tusks of other mammoths will show how often mammoths died in this way and reveal other details from their daily life, indicating the reasons for the disappearance of the largest representatives of the Ice Age megafauna.

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