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 U.S. In 2015, the U.S. Fish and Wildlife Service published a draft conservation management plan for polar bears to improve their status under the Endangered Species Act and the Marine Mammal Protection Act. Polar bear population sizes and trends are difficult to estimate accurately because they occupy remote home ranges and exist at low population densities. Polar bear fieldwork can also be hazardous to researchers. As of 2015, the International Union for Conservation of Nature (IUCN) reports that the global population of polar bears is 22,000 to 31,000, and the current population trend is unknown. Nevertheless, polar bears are listed