Thirteen thousand years ago, North America was teeming with large mammals.
Thirteen thousand years ago, North America was teeming with large mammals. But suddenly these animals (called “megafauna,” meaning a mammal that weighs more than 100 pounds at maturity) began going extinct. Within a thousand years, researchers estimate that over half of the North American megafauna species were gone forever, including woolly mammoths, Columbian mammoths, American mastodons, three types of ground sloths, glyptodonts, several species of horses, four species of pronghorn antelopes, three species of camels, giant deer, several species of oxen, and the giant bison. What happened to them? There are two leading hypotheses. One, called the “Overkill Hypothesis” notes that the disappearance of the species coincided with the arrival of humans in North America, and proposes that humans hunted the now-lost megafauna to extinction. Not having evolved in the presence of humans, the hypothesis goes, the animals had not developed the innate sense to avoid humans, leaving them esp...