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 and Beaufort seas, polar bears retreat each summer to the ice further north that remains frozen year-round. The only other bear similar in size to the polar bear is the Kodiak bear, which is a subspecies of brown bear. Adult male polar bears weigh and measure in total length. Around the Beaufort Sea, however, mature males reportedly average . Adult females are roughly half the size of males and normally weigh , measuring in length. Elsewhere, a slightly larger estimated average weight of was claimed for adult females. When pregnant, however, females can weigh as much as . The polar