Mammals are a diverse group of vertebrate animals that have hair or fur and produce milk to feed their young. They are endothermic which is also known as warm-blooded. Mammals are divided into three groups; monotremes, marsupials and placentals.
Monotremes include both echidnas and platypus, which are the only mammals that lay eggs and do not have teats, the milk is secreted by pores on the female’s belly.
Marsupials are a large group with over 200 Australian species, including koalas, kangaroos and Tasmanian devils. Marsupials give birth to small, poorly developed young. Many species in this group have a well-developed pouch which is a skin fold over the teats with a single opening.
Placentals generally give birth to well-developed young, there are over 140 Australian species in this group including many species of bats and rodents.