Paleo-Eskimos disappeared ten centuries ago, but the mystery surrounding their fate has only recently become known to researchers. North America's Arctic regions were populated by people for 4,000 years, and the group was isolated from the rest of the world, according to a new study.

Paleo-Eskimos first came to Arctic regions of North America from Siberia around BCE 3000. The group never grew larger than around 3,000 people, but they developed a unique culture, with their own deep-set traditions.

Previous studies of the first humans reaching the New World suggested people arrived in three waves. The first of these took place 15,000 years ago, and the most recent was the arrival of the Thule, or proto-Inuit around the year CE 1000. This new discovery adds a fourth round of migrations to the proposed time line, the third of the events in chronological order.

Paleo-Eskimos were able to survive harsh conditions, but would occasionally be forced to temporarily seek warmer climes in southern Canada, populated by Native American tribes. When warmer weather returned, the group would travel north once more. Strangely, genetic markers show little to no interbreeding between Native Americans and Paleo-Eskimo populations.

"When we see people meeting each other, they may fight each other, but normally they also have sex with each other. That does not seem to be the case here," Eske Willerslev, from the University of Copenhagen, said.

Paleo-Eskimos were highly-tied to the natural world, and were slow to change their customs, according to studies. Mitrochondrial DNA, passed from mother to children, was found to be identical among all Paleo-Eskimos tested. This suggests few women were among the first settlers from across the Bering Strait. Previous research suggested this group could have consisted of as few as 40 to 50 members, who were likely closely related.

The Thules were a maritime culture, hunting whales, living in well-managed villages and traveling by bobsled. Dorsets hunted using stone-tipped weapons and lived in small groups of 20 to 30 people.

The group, along with the Dorsets, disappeared about the same time the Thule people migrated into the high Arctic. The newcomers, unlike most of their neighbors, were able to create metal tools and weapons from meteorites discovered on the tundra. However, there is no record of any violent conflict between Dorsets and Thules.

The most likely fate of the Paleo-Eskimos was that the people fragmented into small groups once again, and set on migrations across the northern reaches of the continent. The smaller groups may have found new locations around the frozen expanse, the study reveals.

Investigation of the ultimate fate of Paleo-Eskimos was detailed in the journal Science.