Scientists Baffled by Island's Ancient Bear Bones May Have a Breakthrough

Scientists may have had a breakthrough that will help solve a decades-old mystery involving ancient bear bones discovered in the Aleutian Islands, in Alaska.

Brown and polar bear bones dating back thousands of years were discovered on Alaska's Unalaska and Amaknak islands in the early 2000s—But bears have never lived on those islands. The polar bear bones are about 5,500 years old, while the brown bear bones could be between 3,000 and 5,500 years old, scientists found after subjecting them to carbon dating.

Lilly Parker and Kaylee Tatum, researchers at the University of Oklahoma, have spent two weeks in Unalaska trying to get to the bottom of the strange finding, and while the mystery remains, they are pursuing one theory that bear carcasses were brought to the islands by people as a source of food.

"Regarding the origin of the bears—with the information we have now, we can't tell if the bears lived and were hunted in Unalaska or were transported as a result of trade or long-distance hunting trips," Parker told Newsweek. "We know that Unangan ancestors traveled and traded, and we also know that the climate was colder at the time the bears lived (~5,500 years ago) than it is today, so either scenario is possible."

The sites where the bones were found were once used as dumping grounds by the Unangax̂ people—the indigenous people of the Aleutian Islands, KUCB reported.

The researchers spoke to Unangax̂ elders about possible theories.

"While we were in Unalaska, we asked local people what their hypothesis is about the bear's origin. Many people think that the bears were transported after hunting trips or through trade networks," Parker said.

Thousands of years ago people may have brought bear meat to the islands from Unimak—a neighboring island that did have its own population of the animals. While there are no historical records confirming this, oral tradition suggests people may have eaten bears that long ago, KUCB reported.

Parker told Newsweek that among the bones was a femur that belonged to a bear fetus.

"To me, the presence of a fetus suggests butchering occurred in place in Unalaska, but the female bear could have been transported post-mortem. It's still a mystery," Parker said.

While they haven't been able to confirm that practice, it's something for the researchers to go off as they continue hunting for clues. The theory would make sense as other types of food may well have been scarce there during the long, harsh winters.

"Our next steps are to analyze deep DNA sequence data from all of the bear bones to search for more clues about their origin," Parker said. "Our preliminary data showed us that the DNA from the bones is remarkably well preserved so we hope to be able to tell which modern-day bears the Unalaskan bears are most closely related to. We are planning to return to Unalaska to share our new findings with the community!"

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Update 10/6/23, 3:24 a.m. ET: This article was updated with comment from Lilly Parker.