A study of a 12,800-year-old skull of a toddler offers a glimpse at how early Americans found food, and how their hunts may have led to a mass extinction.
For millions of years, North America was home to a zoo of giants: mammoths and mastodons, camels and dire wolves, sloths the size of elephants and beavers as big as bears. And then, at the end of the Pleistocene Epoch about 12,000 years ago, most of them vanished.
Scientists have argued for decades about the cause of their extinction. Now, a study analyzing the ancient bones of a young child who lived in Montana suggests that early Americans hunted mammoths and other giant mammals to oblivion.
“I was surprised to see things fit so nicely,” said Ben Potter, an archaeologist at the University of Alaska Fairbanks and an author of the new study, which was published on Wednesday in the journal Science Advances.
For decades, most paleontologists blamed the climate for the disappearance of North America’s megafauna. Their extinction coincided with the end of the last ice age, a time when the planet quickly warmed and glaciers retreated northward. The large mammals appeared unable to adapt.
But in the 1960s, the American geoscientist Paul Martin challenged that hypothesis. The last ice age was part of a cycle of warming and cooling that had lasted for millions of years. Why had the megafauna survived earlier periods of warming, but not this one?
Martin believed that the difference was people. At the time, researchers were discovering some crucial clues about how humans had spread from Asia across the Bering Land Bridge into North America. They discovered that the oldest known archaeological remains in North America — stone spearheads known as Clovis points — dated to the end of the ice age, suggesting that their arrival coincided with the extinctions.