whether Homo sapiens' arrival in Australia was the direct cause of the megafauna extinctions. One notable feature of the animal types present on the continent during the Pleistocene was the lack of carnivores: in fact, these animals were almost conspicuous by their absence. Therefore, the large Australian herbivores did not, for the most part, coevolve with an array of predators. As a result, these animals tended to be good sprinters, but poor long distance runners. Obviously, they would have been easy prey for early human hunters. Such facts have given rise to an "overkill hypothesis." Certain researchers believe that rampant overhunting by humans resulted in the megafauna extinctions (Martin 376-397).
Unfortunately though, the archaeological evidence has provided little support for the overkill theory. For example, Pleistocene kill sites discovered thus far in Australia have provided little biological data. No single site has yet been found that satisfactorily shows a "prolonged overlap of humans and classic megafauna (Gillespie et al. 1044-1047)." Although there are rare exceptions, most of the bones found in association with human occupation have belonged to living species (Martin 376-397).
Some researchers note that the lack of observed megafauna kill sites may result from a "blitzkrieg" type of mass extinction (Martin 376-397). This would involve hunting of such high intensity that there would be little association between the first human invaders and their prey. In fact, paleontologists have noted that, in general, an "effective new invader need not overlap in the fossil record with the species it replaces (Martin 376-397)." Thus, vulnerabl
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