Arctic Animal Life
Walrus's have thick skin to protect them from the cold, and they have thick tusks to break through ice. On land the walrus doesn't have predators, so it doesn't need to be fast but in the water it does. Also walrus's have no outer ear, so it helps retain heat. Arctic wolves and foxes have the same adaptation. They can change the color of their fur to blend in against the snow. Polar bears do the same thing. Beluga whales have thick skulls to break ice, and their white coloring makes them hard for predators to find.
Like most marine mammals, narwhals have thick layers of blubber to protect them from the freezing water. Narwhals are virtually blind, so they have a good sense of smell. The lone tusk is actually a front tooth, the males use it to fight and to impress females.