From Wikipedia, the free encyclopedia
The polar bear (Ursus maritimus) is a hypercarnivorous species of bear. Its native range lies largely within the Arctic Circle, encompassing the Arctic Ocean and its surrounding seas and landmasses, which includes the northernmost regions of North America and Eurasia. It is the largest extant bear species, as well as the largest extant land carnivore.
Although it is the sister species of the brown bear, it has evolved to occupy a narrower ecological niche, with many body characteristics adapted for cold temperatures, for moving across snow, ice and open water, and for hunting seals, which make up most of its diet.
Naming and etymology
Constantine John Phipps was the first to describe the polar bear as a distinct species in 1774 in his report about his 1773 expedition towards the North Pole. He chose the scientific name Ursus maritimus, the Latin for "maritime bear", due to the animal's native habitat.
The Inuit refer to the animal as nanook (transliterated as nanuq in the Inupiat language). The Yupik also refer to the bear as nanuuk in Siberian Yupik. In Russian, it is usually called бе́лый медве́дь (bélyj medvédj, 'white bear').
Taxonomy and evolution
The bear family, Ursidae, is thought to have split from other carnivorans about 38 million years ago. The subfamily Ursinae originated approximately 4.2 million years ago. The oldest known polar bear fossil is a 130,000 to 110,000-year-old jaw bone, found on Prince Charles Foreland in 2004.
Fossils show that between 10,000 and 20,000 years ago, the polar bear's molar teeth changed significantly from those of the brown bear. Polar bears are thought to have diverged from a population of brown bears that became isolated during a period of glaciation in the Pleistocene.
Source: Wikipedia