The order Marsupialia forms a diverse group of animals. The members belonging to this order are restricted to the New World and the Australian region. They inhabit a wide range of habitats ranging from desert to rain forest. Their size varies from a small marsupial mouse (e.g. planigale) to a large kangaroo. The single order Marsupialia has been classified into two sub-orders: Polyprotodonta and Diprotodonta. The animals of this order are kangaroo, wallaby, rat kangaroo, koala, wombat, glider, cuscus, bandicoot, marsupial mole, Tasmanian tiger, numbat, etc. Many marsupials are very popular pet animals. Some members are hunted locally for food and other products. Cats, foxes, wild dogs, owls, birds of prey and snakes are their natural predators. Their populations have been declined due to several factors including change of climate, forest fire and encroachment of cultivated land.