"Look at those Atlantic walruses! The walrus has whiskers called vibrissae that it uses to find food, a thick layer of blubber to protect it from cold, and ivory tusks which can grow up to a metre long. It's also known for the various sounds it can make. Actually, if you managed to find a walrus' tusk, you can count the number of rings in it to find out its age, just like counting the number of rings inside the tree. The walrus lives up to 40 years old and can weigh up to 2 tonnes, heavier than the polar bear. It can also hold its breath long enough to dive 500 metres underwater."