What divers found in a Florida sinkhole may help overturn a long-held theory—that people first colonized the Americas thousands of years ago by crossing the Bering Strait, the Guardian reports. Scientists say that fossilized dung, mastodon bones, and a stone knife discovered at the site near Tallahassee suggest people lived there roughly 14,500 years ago. That's about 500 years before the ice-free corridor—land sandwiched between ice sheets in the US and Canada—appeared, allowing those who crossed the Bering Strait land bridge to travel throughout the continent, Smithsonian notes. "So the ice-free corridor is not our answer for how the Americas were initially colonized," says Jessi Halligan, an anthropologist whose team went searching in the Aucilla river sinkhole between 2012 and 2014. They pulled out a few stone tools, including one known as a "biface" that Halligan says was "absolutely" made by people.
They also re-analyzed a mastodon tusk retrieved earlier at the site and say deep marks in its surface were cut by humans. Other animal bones found at the sinkhole include dire wolf, mammoth, horse, camel, giant armadillo, sloth, and even dogs, who may have accompanied or trailed the hunters, Discovery reports. So if these people didn't come by Bering Strait, how did they? "The only logical way people could have come to Florida [from Asia] 14,600 years ago is if their ancestors entered the Americas by boat along the Pacific Coast," says anthropologist Michael Waters, who worked with Halligan. "They could have traveled by boat to central Mexico, crossed and come along the Gulf Coast." Published in Science Advances, this is one of a few finds challenging the notion that people first came to the Americas about 13,000 years ago. (Read more anthropology stories.)