Giant mammals once inhabited every continent, sometimes accompanied by huge birds and reptiles. The fact that only in Africa have many species survived may indicate that human arrival proved disastrous for animals that were not used to our presence.
However, some fossil specimen dates are thousands of years after human arrival (AS, August 2005, p.12), challenging the idea of a rapid extinction. Supporters of the human involvement theory have pushed back, questioning the dating involved for these sites.
Now A/Prof Stephen Wroe of the University of NSW has challenged human involvement from the other direction. He claims that roughly 90 species can be included in the Australian megafauna category, and of these between eight and 14 were still alive when people arrived in Australia 50,000 years ago. Many species disappear from the fossil record 130,000 years ago, around the time the world reached maximum glaciation and Australia was unprecedentedly dry.
Wroe acknowledges that humans may have eliminated the last few species but regards even this as uncertain. “There has never been any direct evidence of humans preying on extinct megafauna in Sahul [Australia joined to New Guinea] or even of a toolkit that was appropriate for big-game hunting.” Wroe says the first Aboriginal settlers were “by definition, marine people” who would have slowly spread around the...
