For years, scientists have believed that humanity was a relatively recent visitor to the North American continent, migrating from Siberia only 15,000 years ago. Now, more accurate dating of mastodon fossils from California shows that an early human ancestor likely existed on the continent 130,000 years ago, far further back than even the most extreme estimates made by previous researchers.
The fossils consist of elephant-like teeth and bones, which were discovered in Southern California during the construction of an expressway in 1992. The fossils bear clear signs of deliberate breakage using stone hammers and other early human tools – but until recently, dating technology was not sophisticated enough to accurately pinpoint the era from which they originated.
Using new methods to measure traces of natural uranium in the bones, researchers with the US Geological Survey and the Center for American Paleolithic Research found these bones were far older than the era when humans are generally accepted to have lived in America.
While these people were clearly somehow related to modern-day humans, and were advanced enough to create and use stone tools, researchers say that they wouldn’t have been Homo sapiens as we know them. Our species didn’t leave Africa until 80,000 to 100,000 years ago. Instead, some likely candidates are Homo erectus, the Neanderthals, or perhaps a little-known hominid species called the Denisovans, whose DNA can still be found in Australian aboriginal populations today.
It’s likely this ancient human population died out before Homo sapiens eventually crossed the Pacific. It’s believed they did not interbreed with modern humans and likely are not direct ancestors of any Native American groups. The new findings have been published in the journal Nature.
Images via San Diego Natural History Museum