Koala
Phascolarctos cinereus

Probably one of the best-known Australian animals, the Koala is also one that is facing questions about its long-term survival. Fragmentation of bushland prevents Koalas from mixing to breed, leading to shallow gene pools and decreasing resistance to the diseases that can infect them. They spend most of their time asleep, sleeping for about 19-20 hours a day and sharing the rest between feeding and resting. Their diet is almost exclusively made up of eucalyptus leaves, which most other animals find too toxic. The leaves are also poor in nutrients, so Koalas have to eat a lot and take a lot of time in chewing and digesting them. South Australia's Koalas (of which the one pictured here is one) are from transplanted stock from Victoria where they are doing well after the original SA populations were exterminated in the early 1900s for fur.
 

1: Park 19, Adelaide, SA, 29/08/2012.