Moscow, Jun 13 (IANS/RIA Novosti): Prehistoric hunters are not to blame for mammoths becoming extinct in Russia's far eastern region, a new joint Russian-American study has said.

The reason why mammoths went extinct around 11,500 years ago in Beringia region, comprising modern day Chukotka, Alaska and far eastern reaches of Siberia, was severe cooling of climate, according to the study published in Nature Communications online magazine.

Taiga and swamps replacing steppes in the region's south also contributed, said the study led by Glen Macdonald of the University of California, Los Angeles.

The academic community has no consensus on what caused the extinction of megafauna such as mammoths at the end of late Pleistocene, when modern humans appeared.

Some researchers blame overhunting while others put the process down to climate change.

The new study supports the latter theory, with researchers examining remnants of some 1,300 Beringia mammoths and 1,000 samples of soil fossils to determine the reasons for mammoths' extinction.

A climate change destroyed the shrubs and herbaceous plants that the animals fed on, replacing it with swamp vegetation in the region's north, the study said.

The mammoths migrated south, but another climate change that destroyed the region's steppes wiped out most of them, the study said.

Human input was minimal, it said.

Isolated mammoth populations survived on remote Arctic islands until the second millennium B.C., archeological data show.