During migration, polar bears reach mainland by ice. The exit to the coast is extremely important for them, as bears find food there - remains of walrused perished at coastal breeding-grounds, remainder of aboriginal population's sea fishery, ringed seal (Pusa hispida). Pregnant females come out to the locations of hiding into maternity dens. Lagging of ice sheet arrival in the south makes a lot of bears reach mainland by swimming.
In 2005, reports appeared that polar bears were more frequently found swimming in the open sea in the direction of the mainland. The animals often die as they are not adapted to lengthy stay in the open sea, where roughness is high in contrast to water areas covered by ice. The bears that reached the mainland are exhausted and hungry. Thus makes them particularly vulnerable, as the animals lose caution in search of food, come out to villages and sometimes attack people.
One more inhabitant of the Arctic Zone the walrus suffers from the effects of global warming. At the beginning of autumn migration, walruses have to overpass hundreds of kilometers from the edge of the ice up to the Arctic coast of Chukotka, where they can rest in coastal breeding-grounds before they finally leave the Chuckchee Sea. Previously, longstanding drift-ice was always present to some extent at an insignificant distance from the coast, providing walruses with a platform for rest during their migration from the north to the south.
Hunters from coastal villages point out that walruses come to the breeding-grounds very exhausted. Therefore, if something prevents them from coming out into the coast, the animals (particularly young walruses and walrus-calves of the first year of life) may perish.
Since 2003, the WWF has been executing the polar bear preservation project in Chukotka. The project includes support of the Wrangel Island reserve, "maternity hospital" for polar bears, and establishment of secured territories along the coast. A very important part of the project is the polar bear migration monitoring in the area of coastal villages along the Chuckchee Sea, where appearance of these animals in autumn period is commonplace.