Scientists at the US Minerals Management Service have for the first time found evidence that polar bears are drowning because climate change is melting the Arctic ice shelf.
The bears have to swim up to 60 miles across open sea to find food. Their long sea journeys leave them vulnerable to exhaustion, hypothermia or being swamped by waves. Four bear carcases were found floating in one month in a single patch of sea off the north coast of Alaska.
The research comes amid evidence of a decline in numbers of the 22,000 polar bears that live in about 20 sites across the Arctic circle.
Researchers working for the World Wildlife Fund in Yakutia, on the northeast coast of Russia, have also found the region’s first evidence of cannibalism among bears competing for food supplies.