Polar Bear

Ursus maritimus
Family: Ursidae
polar bear

Photo © Alaska Stock

skull

See a 3-D animation of a polar bear skull.


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polar bear range map

Distribution/Migration: Arctic. From Bering Sea into Chukchi and Beaufort seas. Seasonal movement with ice: north in summer as ice recedes from coast, south with advancing ice in fall. Pink shows summer range, blue shows winter range, and purple shows year-round range.


This web page is modified from the book Marine Mammals of Alaska by Kate Wynne, illustrated by Pieter Folkens, available at the Alaska Sea Grant Bookstore.

Marine Mammal Guide

SIZE: Average adult male 8.5 ft (2.6 m), 900 lbs. Average adult female 6.5 ft (2 m), 500 lbs. At birth: 10 in (0.3 m), 1-2 lbs.

BODY: Large, long-legged bear with dense fur and blubber layer. Prominent snout and short, round, furred ears.

COLOR: White with black eyes, nose, and lips.

BEHAVIOR: Usually solitary except female-cub groups or near abundant food source. Pregnant females den up for winter but do not hibernate. All age and sex classes may den temporarily to avoid harsh weather. Very inquisitive, with an acute sense of smell. Swim with head above water, dog-paddling with front legs. Dive to approach basking seals at edge of floes or to flee from humans.

HABITAT: Spend entire life associated with pack ice. Females may prefer shorefast ice while others prefer moving sea ice at the floe edge. Usually within 180 mi of shore.

FOOD HABITS: Eat primarily ringed and bearded seals. Catch seals mainly by still-hunting at breathing holes, haul-outs, and lairs, or stalking basking seals. Occasionally eat other mammals, eggs, vegetation, beach-cast carrion.

LIFE HISTORY: Sexually mature at 4–8 yrs. Breed polygamously April–June. 1–3 cubs every 28 mos. Pregnant females dig a den October–December where cubs are born December–January and stay until March–April. Lactation lasts 28 mos. May live to 25–30 yrs.

STATUS AND HUMAN INTERACTION: Population apparently healthy. Approx 3–4000 in Alaska. Sport hunters killed approx 200 per yr from 1940s until banned in 1972. Subsistence use (for hide, meat, handicraft) by Alaska Natives <100 per yr. Loss of sea ice threatens denning and foraging of this ice-dependent species.