Marine mammals are divided between the orders Cetacea, Sirenia, and Carnivora. Whales, dolphins, and porpoises are in the order Cetacea. Manatees and dugongs are in the order Sirenia. Seals, sea...
The echidna and the platypus are non-placental mammals. They are monotremes, or egg-laying mammals. Kangaroos, wallabies, koalas, bandicoots, wombats and Tasmanian devils are just a few other...