Wrangel Island

The last ones died out on Wrangel Island off Siberia's coast 4,000 years ago.

And last week, Eric Regehr, a University of Washington, Seattle, biologist, abandoned plans to join Russian researchers on remote Wrangel Island in an annual campaign, supported by the U.S.

This year, polar bears will cross from Alaska to Siberia as they do every spring, plodding across the frozen Chukchi Sea to their summer home on Russia’s Wrangel Island.

In recent years, U.S. and Russian scientists converged on Wrangel Island, where as many as 1000 of the animals spend part of the summer.

"We know that mammoths and Asian elephants diverge somewhere between 5 and 6 million years ago. We know that they were widespread throughout the ice ages, lived everywhere across the northern hemisphere, and survived for the longest on the isolated islands like Wrangel Island and Saint Paul Island."