Polar bear the fourhorn sculpin. With the exception of pregnant females, polar bears are active year-round, although they have a vestigial hibernation induction trigger in their blood. Unlike brown and black bears, polar bears are capable of fasting for up to several months during late summer and early fall, when they cannot hunt for seals because the sea is unfrozen. When sea ice is unavailable during summer and early autumn, some populations live off fat reserves for months at a time, as polar bears do not 'hibernate' any time of the year. Being both curious animals and scavengers, polar bears investigate and
Polar bear is referred to as "ours blanc" ("white bear") or "ours polaire" ("polar bear"). In the Norwegian-administered Svalbard archipelago, the polar bear is referred to as "Isbjørn" ("ice bear"). The polar bear was previously considered to be in its own genus, "Thalarctos". However, evidence of hybrids between polar bears and brown bears, and of the recent evolutionary divergence of the two species, does not support the establishment of this separate genus, and the accepted scientific name is now therefore "Ursus maritimus", as Phipps originally proposed. The bear family, Ursidae, is thought to have split from other carnivorans about 38 million years