The great beasts vanish

The pattern is the strongest argument: Australia loses its megafauna around 45,000 years ago, the Americas around 13,000, Madagascar and New Zealand less than a thousand years ago — each time just after human arrival, and independently of the climate cycles that came and went throughout. Africa, where animals had evolved alongside humans, lost the least. Climate change at the end of the last glacial probably contributed, but does not explain the timing on its own. The loss was ecologically pervasive: large herbivores shape vegetation, disperse seeds and move nutrients over long distances.