- bb02babyLv 71 decade agoFavorite Answer
The polar bear (Ursus maritimus), also known as the white bear, northern bear, sea bear, ice bear or nanuq in some Inuit languages, is a species of bear that is native to the Arctic and the apex predator within its range. Its thick blubber and fur insulate it against the cold. Its fur, commonly mistaken as white or cream-colored due to the way light refracts within each hair, is translucent, providing camouflage from its prey. The bear has a short tail and small ears that help reduce heat loss, as well as a relatively small head and long, tapered body to streamline it for swimming. The polar bear is a semi-aquatic marine mammal that depends mainly upon the pack ice and the marine food web for survival. It has uniquely adapted for life on a combination of land, sea, and ice and is now dependent on this combination.
Scientists and climatologists believe that the projected decreases in the polar sea ice due to global warming will have a significant negative impact or even lead to extinction of this species within this century.
An alternative theory downplays the effect climate change is having on the polar bear and hypothesizes that the species may survive through adaptation.
Polar bears rank with the Kodiak bear as among the largest living land carnivores, and male polar bears may weigh twice as much as a Siberian tiger. There is great sexual dimorphism, with some males reaching more than twice the size of the females. Most adult males weigh 300-600 kg (660-1320 lbs) and measure 2.4-3.0 m (7.9-10.0 ft) in length. Adult females are roughly half the size of males and normally weigh 150-300 kg (330-660 lbs), measuring 1.9-2.1 m (6.25-7 ft).At birth, cubs weigh only 600-700 g or about a pound and a half.