Marsupials
Marsupials are the most famous mammals in Australia, and are the most diverse group of mammals across the continent. They range from the tiny Pygmy Possums to the largest of all, the Red Kangaroo, which can stand taller than a grown man.
Monotremes
Monotremes are egg-laying mammals. The most famous is the platypus, but the echidna is more frequently seen.
Pinnipeds
Pinnipeds are the seals and sea lions (and walruses in the Northern hemisphere).