Climate change not the actions of humans, is likely to have led to the dying out of Australia's giant wombats, and kangaroos , according to a new study. Gilbert Price, who is studying for his PhD at Queensland University of Technology, has been analysing fossils found on a site at Darling Downs in southeast Queensland. Among the remains of the 44 species found are those of some of Australia's extinct megafauna , the hippo sized wombat or diprotodon and the giant kangaroo, which grew to more than three metres(10 feet ) tall.