The tusk of an ancient mammoth helped to reconstruct his biography

The tusk of an ancient mammoth helped to reconstruct his biography
The tusk of an ancient mammoth helped to reconstruct his biography
Anonim

The isotopes in the annual rings of the mammoth tusk made it possible to map its movements in Alaska - from birth in the Yukon Valley to death 28 years later, far in the north of the peninsula.

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Most of the mammoths died about 10 thousand years ago, when the last ice age ended. Individual populations have existed for much longer, but they also disappeared four to five thousand years ago. However, the permafrost perfectly preserved their tissues, making it possible to extract and examine cells, DNA, and even hope for a possible restoration of the species. And recently Matthew Wooller of the University of Alaska Fairbanks and his colleagues analyzed not only DNA, but also the isotopic composition of a 1.7-meter tusk found in the northern United States.

The tusk is dated to about 17 thousand years old, when the future extinction was not yet felt, and belonged to a male who made unhurried but constant migrations along the ancient tundra steppe. Judging by the estimates of scientists, for 28 years of its life (which is easily established by the "annual rings" on the tusk) the mammoth traveled a distance approximately equal to two Earth's equators. They write about this in an article published in the journal Science.

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The tusk grows in rings, and year after year, isotopes from plants that the mammoth ate were included in its composition. This is how the detailed "chronicle" of his travels was preserved, which was reconstructed step by step by biologists. They carried out over 340,000 individual measurements of oxygen isotopes as well as strontium. An "isotope map" of Alaska has already been compiled on the basis of similar studies of rodent teeth. Therefore, scientists compared the data obtained from the mammoth tusk with this map, and determined the routes of its migrations, and with a huge resolution - literally by weeks.

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The mammoth roamed nearly all of Alaska, although the preferred areas varied with the age of the animal. He spent the first years of his life in the Yukon River basin and did not go far. Between two and 16 years old, he began to graze in a confined space, and then his range increased sharply again. Scientists attribute this to the fact that at first the young mammoth moved with the herd, and, having reached adulthood, began to live independently.

In the last years of its life, the area on which the mammoth grazed sharply decreased and was reduced to a relatively small area in northern Alaska. Here he was starving (as evidenced by an increased nitrogen-15 content and a decrease in carbon-13 coming from plants) and eventually died, being buried in the permafrost until 2010, when scientists dug up the remains.

It is curious that many of the mammoth routes coincide with the modern migration trails of local caribou, reindeer, as well as the campsites of the first inhabitants of Alaska. Perhaps in the future this will make it easier to find such places.

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