Reproduction: The testes are abdominal like echidna. Females have no teats. Platypus is sexually mature at about five years of age. The mating is supposed to occur in water during the months of July to October. They usually lays two soft eggs and the young are hatched
after a period of 7-12 days of incubation periods. Young are nursed for about 3-4 months.
Behaviour: When the animal lives under water, its eyes and ears are closed by a fold of skin. The two small internal cheek pouches are used for storing of food. It digs a burrow in the bank of lake, stream etc and builds the nest at the terminal point of the burrow. Platypus is reported to build two types of burrows - one is used for taking shelter and other one is for rearing the young.