An ancient brown bear fossil found on Japan's Honshu Island, today home to Tokyo, belongs to a previously unknown bear lineage, LiveScience reports.
Researchers led by the Tokyo Institute of Technology's Hidenori Nishihara analyzed mitochondrial DNA obtained from a 32,500-year-old brown bear fossil found on Honshu. Currently, brown bears only live on the island of Hokkaido in Japan, but fossil evidence has suggested that they were more widespread during the Pleistocene. As they report in Royal Society Open Science, the researchers compared this bear's mtDNA to that of other ancient and modern Ursus arctos to find that it belongs to a previously unknown bear lineage that diverged from the Hokkaido bears about 160,000 years ago.
As Live Science notes, the finding suggested to the researchers that the bears crossed the Tsugaru Strait between Hokkaido and Honshu around that time. It adds that other animals like Naumann's elephants and the giant deer also appear to have made the crossing around then when sea levels are thought to have been low.