What Happened to the Megafauna?: A Selection from Joseph Henrich’s The Secret of Our Success (2017)
“Not only did ancient hunter-gatherers expand into most of the earth’s terrestrial ecosystems, we probably also contributed to the extinction of much of its megafauna—that is, to the extinction of large vertebrates like mammoths, mastodons, giant deer, woolly rhinos, immense ground sloths, and giant armadillos, as well as some species of elephants, hippos, and lions. While climatic shifts were also likely contributors to these extinctions, the disappearance of many megafaunal species eerily coincides with the arrival of humans on different continents and large islands. For example, before we showed up in Australia around 60,000 years ago, the continent was home to a menagerie of large animals, including two-ton wombats, immense meat-eating lizards, and leopard-sized marsupial lions. These, along with 55 other megafaunal species, went extinct in the wake of our arrival, resulting in the loss of 88% of Australia’s big vertebrates. Tens of thousands of years later, when humans finally arrived in the Americas, 83 genera of megafauna went extinct, including horses, camels, mammoths, giant sloths, lions, and dire wolves, representing a loss of over 75% of the existing megafauna. Similar patterns emerged when humans arrived at different times in Madagascar, New Zealand, and the Caribbean.
Sharpening the point, the megafauna of Africa, and to a lesser extent of Eurasia, fared much better, probably because these species had long coevolved over hundreds of thousands of years with humans, including both our direct ancestors and our evolutionary cousins like the Neanderthals. African and Eurasian megafauna evolved to recognize that while we appear rather unintimidating, and perhaps easy prey given our lack of claws, canines, venom, and speed, we come with a dangerous bag of tricks, including projectiles, spears, poisons, snares, fire, and cooperative social norms that make us a top predator. It’s not just the fault of industrialized societies; our species’ ecological impacts have a deep history. . . .
There remains much debate about the forces contributing to these extinctions, including the hypothesis that humans transmitted diseases to megafauna. In total, however, it seems likely that humans made substantial contributions to many of these extinctions, through both direct hunting and indirect effects such as fire (expansive burning in Australia) and other ecological disturbances (competition with other top carnivores).”—Joseph Henrich, The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter (2017)
