Bear Species
Polar Bear
( Ursus maritimus )

Polar bear (Ursus maritimus) (cc) www.kewlwallpapers.com
(cc) www.kewlwallpapers.com

Physical description and lifespan

Polar bears are similar in size to brown bears. Adult males are usually 2.0 to 2.6 m in length and can weigh 350–700 kg; adult females are approximately 1.8 to 2.0 m in length, typically weighing 150–300 kg. Polar bears appear to have a more elongated body form than other bears

This species has serrated teeth that are well adapted to their diet of marine mammals, primarily ringed and bearded seals. Polar bears are known to scavenge the carcasses of walrus and beluga, narwhales and bowhead whales.

Polar bears have black skin, covered entirely by white fur covering except for the nose. The species has a dense under-fur with intermediate length guard hairs.

The maximum lifespan of a Polar bear may approach 25–30 years. The primary causes of natural mortality are starvation, accidents, and intraspecific predation (largely adult males eating cubs unrelated to them).

Distribution

Polar bears have a circumpolar distribution, meaning they are found throughout the arctic regions of the northern hemisphere. There are 18 discrete populations, often living several hundred kilometers offshore from land masses.

Reproduction

Polar bears mate from March to June and ovulation appears to be brought on by mating. The entire gestation period is approximately 195–265 days with birthing occurring from November to January. Litter sizes range from one to four cubs and average 1.6–2.0. Polar bear cubs are suckled until approximately 24–28 months of age.

Although many Polar bear populations remain on the pack ice all year, others leave during summer months. Once ashore they can become ‘conflict bears’, particularly around petroleum exploration and extraction camps. This species is known to habituate to people easily and feed extensively on garbage around settlements.

2008 conservation status

Polar bears are classified as ‘VU’ (vulnerable) on the IUCN 2006 Red List, primarily as a result of declining habitat quantity and quality. Global warming is expected to have a negative impact on some Polar bear populations, but other populations may benefit in the short-term.

Back to top >>