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DNA analysis from the remains of mastodons from all over North America showed that these majestic animals could make long journeys, mastering the Northern territories, but as a result, they only died out faster.

As the climate warms, some species may expand their range, moving further North: this was the case with American mastodons, relatives of our mammoths, during the interglacial periods. However, this spread only led to a reduction in genetic diversity and accelerated the extinction of woolly proboscis giants.

The oldest remains of American mastodons (Mammut americanum) appear between 4 and 3.5 million years ago. They grazed among trees and shrubs in the swampy lowlands of North America until about 11 thousand years ago, when they completely disappeared — as it is believed, under the simultaneous blows of warming and people who came to the continent. To trace their fate, scientists from Canada's McMaster University extracted and analyzed the complete mitochondrial DNA of 35 mastodons-from 33 ancient bones, one tooth and one Tusk.

It was found that mastodon populations were not stationary and moved slowly, following pastures: the Pleistocene epoch in which these animals lived was a time of constant changes of cold ice ages and relatively warm interglacial periods. Scientists have shown that mastodons are genetically divided into five separate clusters. Two of them existed far to the North — in Alaska and the Yukon - but at different periods of the interglacial period. This means that these groups appeared as a result of two different migrations.

Their genetic diversity was low, indicating that as the climate cooled, the population declined. Once isolated, they eventually died out. "This is always a bad signal for any vertebrate species," says Grant Zazula, one of the authors of the paper. "If you lose genetic diversity, you lose the ability to adapt to new conditions."

The authors believe that similar processes could have occurred with other animals at that time, including in Eurasia. During warm periods, ancient hippos and hyenas reached as far as Scandinavia. Apparently, they did not return: like mastodons, these populations fragmented, isolated — and died out.

The article is published in the journal Nature Communications

Illustration - © Julius Csotonyi
Source: naked-science.ru, sci-dig.ru