Two separate species of human ancestors may both have occupied a cave in Siberia at the same time thousands of years ago.
Researchers have long been working to narrow down the timeline of hominin occupation at Denisova Cave after a trove of artifacts, including stone tools and bone points, were found at the site.
A pair of new studies analyzing the discoveries now suggests the site was home to Denisovans as far back as 287,000 years ago, before possibly overlapping with the arrival of Neanderthals 193,000 years ago.
The two new studies published in Nature this week could help to refine our understanding of the extinct hominins’ history.
Much about the Denisovans remains a mystery; though their existence at the site is known from fragments of bone and teeth, the size and complexity of the cave has made it difficult to study.
In one of the new efforts, a team led by researchers from University of Wollongong used a technique known as optically stimulated luminescence dating to analyze sediments from Denisova Cave.
This allowed them to estimate when certain mineral grains were last exposed to sunlight in order to create a timeline for the fossils and artifacts that have been found there.
According to the team, occupation at the site spans from around 300,000 years ago to 20,000 years ago.