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 eggs, rodents, crabs, other crustaceans and other polar bears. They may also eat plants, including berries, roots, and kelp; however, none of these have been a significant part of their diet, except for beachcast marine mammal carcasses. Given the change in climate, with ice breaking up in areas such as the Hudson Bay earlier than it used to, polar bears are exploiting food resources such as snow geese and eggs, and plants such as lyme grass in increased quantities. When stalking land animals, such as muskox, reindeer, and even willow ptarmigan ("Lagopus lagopus"), polar bears appear to make use of