Late Pleistocene Megafaunal Extinctions

The modern world is largely bereft of huge animals, the megafauna that roamed the planet during the late Pleistocene. Megafauna are commonly defined as an animal with an adult body weight in excess of 44kg. By the end of the last ice age, a large percentage of terrestrial megafaunal species had become extinct. This article reviews the history of these extinctions in Australia, the Americas, Eurasia and Africa. There are two principal hypotheses to explain these extinctions. The first is that environmental change drove the megafauna to extinction. The second is that these extinctions followed in the footsteps of humans as they entered the various continents. We review the evidence supporting both hypotheses. Finally, we summarize a series of ecological models that have been developed in the last few years, in attempts to arrive at unbiased, independent solutions. Roughly 86% of the Australian megafauna died out before the end of the last ice age. This extinction process apparently began within a few centuries or millennia after the arrival of humans in the interior regions, about 50, 000years ago (50ka). The North American megafauna suffered a 73% reduction in genera by the end of the Pleistocene, and the South America megafauna suffered almost an 80% reduction in genera. The African megafauna lost about 24% of their genera in the last 100, 000years—the smallest faunal decline of any continent. Eurasia, like Africa, suffered relatively few megafaunal extinctions in the late Pleistocene.