The polar bear is the largest animal in the bear family, body length of up to 2.5 meters, 1.6 meters high, weighing 500 kg. Polar bearsare not only good at swimming in cold water, but also good at quick jump on the ice, the maximum can reach a height of 1.8 metres. As the "king of the Arctic Circle", except for humans, bears almost no natural enemies.希望采纳! 北极熊是熊科动物中最大的,体长可达2.5米,高1.6米,重500公斤.北极熊不仅善于在冰冷的海水中游泳,还擅长在冰面上快速跳跃,最高可以达到1.8米的高度.作为“北极圈之王”,除去人类,北极熊几乎没有天敌
The polar bear (Ursus maritimus) is a bear native largely within the Arctic circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest carnivore species found on land. It is also the largest bear, together with the omnivore Kodiak bear which is approximately the same size.[3] An adult male weighs around 350–680 kg (770–1,500 lb),[4] while an adult female is about half that size. Although it is closely related to the brown bear, it has evolved to occupy a narrow ecological niche, with many body characteristics adapted for cold temperatures, for moving across snow, ice, and open water, and for hunting the seals which make up most of its diet.[5] Although most polar bears are born on land, it spends most of its time at sea, hence its name meaning "maritime bear", and can hunt consistently only from sea ice, spending much of the year on the frozen sea.