The platypus is one of the non-marsupial mammals on the continent of Australia. It is one of the only mammals that lay eggs. The milk from the mammary glands comes through the fur and the young lap it up. The young have teeth but soon lose them after adulthood. The diet of the platypus consists of aquatic insects, worms, small crustaceans, and mollusks. The platypus has dense gray-brown fur. The male, two feet long, has spurs behind the ankle of its back leg. Although only painful to humans, it is fatal to small animals.