What do platypus offspring do?

The male platypus has a spur on each hind foot, which is normally retracted but, when necessary, can be extended. This is hollow, and connected with a gland in the leg, which secretes poison-a poison which is capable of inflicting a painful wound. The young of both sexes are hatched from the eggs, quite naked, and in this state are nourished with milk, secreted from a mammary gland in the skin of the belly; these glands have no nipples, and the milk is simply licked off the hairs of the belly by the young.