The sea bear, Ursus aquaticus, is the direct and only descendant of the polar bear. It appears that, due to the melting ice, polar bears were forced to become aquatic. Due to the fact that polar bears sometimes needed to swim to land and had webbed paws, they were already suited to the water. The result was the sea bear. Sea bears, rather than having thick fur, have quite short fur and a lair of blubber under their skin. Their front paws have become powerful paddles that are there main source of locomotion. Their hind limbs are flippers that help with steering. Unlike the rest of their body, however, the head remains virtually the same as its ice-living ancestor. The sea bear has powerful jaws and large canine teeth that enable it to catch its prey. Its ears have become ear-holes, much like in seals. Sea bears can weigh up to 1,600 lb, 100 lb heavier than their ancestors. The claws on their front flippers enable it to climb onto ice or land if it needs to. The sea bear is the top predator of the arctic seas. Its favorite prey are baluga whales and their relatives, but it also tackles walrus and elephant seals.