It is believed that between 200,000 and 300,000 species are in Australia, but so far only about 100,000 have been described. Mammals all produce milk to suckle their young. Mammals have fur or hair. They are only found in Australia and New Guinea. The Platypus and the Echidna are the only monotremes left today.
Marsupials are mammals that give birth to young which are in an immature state.
The females often have pouches in which to carry the young. Most species are found in other parts of the world. The land masses of the world have not always been where they are today. At one time all the continents were joined together in one land mass called Pangaea. The continents themselves are lighter rocks sitting on top of these plates.