Sunday, April 27, 2008

Monday, April 21, 2008

Entertainment and commerce

Polar bears have been made both controversial and famous for their distinctive white fur and their habitat. Companies like Coca-Cola, Polar Beverages, Nelvana, Bundaberg Rum and Good Humor-Breyers have used images of this bear in logos.

The Canadian 2-dollar coin features the image of a polar bear.

The panserbjørne of the fantasy trilogy His Dark Materials are polar bears with human-level intelligence.

The TV series Lost has featured polar bears on a mysterious tropical island where they are portrayed as fearsome beasts.

Also, a polar bear was chosen as mascot for the 1988 Winter Olympics held in Calgary, Canada.

The Polar Bear is the mascot of Bowdoin college.

The Northwest Territories of Canada have a licence plate in the shape of a polar bear.

Monday, April 14, 2008

Monday, April 7, 2008

Fur and Skin

A polar bear's fur provides camouflage and insulation. Although the fur appears white, in fact the individual hairs are translucent, like the water droplets that make up a cloud; the coat may yellow with age. Stiff hairs on the pads of a bear's paws provide insulation and traction on the ice.

Polar bears gradually molt their hair from May to August. However, they do not shed their coat for a darker shade to camouflage themselves in the summer habitat.

The thick undercoat does, however, insulate the bears: they overheat at temperatures above 10 °C (50 °F), and are nearly invisible under infrared photography; only their breath and muzzles can be easily seen. When kept in captivity in warm, humid conditions, it is not unknown for the fur to turn a pale shade of green. This is due to algae growing inside the guard hairs — in unusually warm conditions, the hollow tubes provide an excellent home for algae. Whilst the algae is harmless to the bears, it is often a worry to the zoos housing them, and affected animals are sometimes washed in a salt solution, or mild peroxide bleach to make the fur white again.

The guard hair is 5-15 cm over most of the body of polar bears. However, in the forelegs, males have significantly longer, increasing in length until 14 years of age. The ornamental foreleg hair is suggested as a form of an attractive trait for females, likened to the lion mane.