When did they become extinct? The debate continues. Are the experts on the horns of a dilemma or do they face an impossible tusk?
Some ancient DNA may be leading paleontologists astray in attempts to date when woolly mammoths and woolly rhinos went extinct.
In 2021, an analysis of plant and animal DNA from sediment samples from the Arctic, spanning about the last 50,000 years, suggested that
mammoths survived in north-central Siberia as late as about 3,900 years ago (
SN: 1/11/22). That’s much later than when the youngest mammoth fossil found in continental Eurasia suggests the animals died out; it dates to about 10,700 years ago. Only on Wrangel Island off the coast of Siberia and the Pribilof Islands in the Bering Sea were mammoths known to have survived later.
The finding was one of several in recent years using ancient DNA found in sediment and other environmental material to suggest new insights into animal extinctions. Genetic evidence from woolly rhinos in Eurasia and horses in Alaska have also indicated that these animals remained thousands of years longer in some areas than was thought.
But thousands of years is also how long the animals’ large bones can linger on the ground in the frigid north, slowly weathering and shedding tiny bits of DNA, two researchers write November 30 in
Nature.
That means that the youngest ancient DNA in sediment samples may have come from such bones, not living mammoths, woolly rhinos and other megafauna. Studies that rely on this genetic evidence could
skew estimates of when these animals went extinct by thousands of years toward the present, say paleontologists Joshua Miller of the University of Cincinnati and Carl Simpson of the University of Colorado Boulder.
When, and why, mammoths and some other Ice Age creatures died out is a lingering mystery. Dating when these animals went extinct could help reveal
what drove them to their demise — humans,
a warming climate, some combination of the two or something else entirely (
SN: 11/13/18; SN: 8/13/20). ...
https://www.sciencenews.org/article/mammoths-extinct-earlier-edna-evidence