Wolves, the wild ancestors of dogs, are the only large predators domesticated by humans. However, it remains unclear whether this process occurred through direct and deliberate human control of wild wolves or whether wolf populations gradually adapted to the human niche. Now, archaeologists have discovered the remains of two canids with genetic origins from the gray wolf in the Stora Førvar cave on the Swedish island of Stora Karlsø in the Baltic Sea. This island is small (2.5 km.2) and, like the neighboring island of Gotland, has no endemic populations of land mammals, meaning that any such animals must have been introduced there by humans.
Canadian Eskimo Dogs by John James Audubon and John Bachman.
“The discovery of these wolves on a remote island is completely unexpected,” said Dr Linus Girdland-Flink, a researcher at the University of Aberdeen.
“Not only did they have an ancestry indistinguishable from other Eurasian wolves, but they seemed to live close to humans, feeding on their food, and in a place they could only reach by boat.”
“This paints a complex picture of relationships between humans and wolves in the past.”
Genomic analysis of the remains of two dogs from the Stora Förvar cave confirmed that they were wolves, not dogs.
However, they did have several traits typically associated with living around humans.
Isotope analysis of their bones revealed a diet rich in marine protein, such as seal and fish, consistent with that of the people on the island, suggesting they were food-sufficient.
Moreover, the wolves were smaller than typical mainland wolves, and one individual showed signs of low genetic diversity, a common result of isolation or controlled breeding.
The findings challenge traditional understandings of the wolf-human relationship and the process of dog domestication.
Although it remains unclear whether these wolves were domesticated, kept in captivity, or otherwise managed, their presence in an isolated environment occupied by humans indicates a deliberate and sustained interaction.
“It was a complete surprise to see that it was a wolf and not a dog,” said Dr. Pontus Skoglund, a researcher at the Francis Crick Institute.
“This is a provocative case that raises the possibility that, in certain conditions, people may have kept wolves in their settlements and found value in it.”
“The genetic data are amazing,” said Dr Anders Bergström, a researcher at the University of East Anglia.
“We found that the wolf with the most complete genome had low genetic diversity, lower than any other ancient wolf we've seen.”
“It's similar to what you see in isolated or restricted populations or in domesticated organisms.”
“While we cannot rule out that these wolves had low genetic diversity due to natural causes, it does suggest that humans interacted with and managed wolves in ways that we have not previously considered.”
One of the wolf specimens, dating back to the Bronze Age, was also found to have severe pathology in the bones of the limb, which limited its mobility.
This suggests that it may have been cared for or was able to survive in an environment where it did not need to hunt large prey.
“The combination of data has opened up new and very unexpected perspectives on Stone Age and Bronze Age human-animal interactions in general and in relation to wolves and dogs in particular,” said Stockholm University professor Jan Ståra.
“The study shows that human-wolf interactions in prehistoric times were more diverse than previously thought, and included complex relationships and interactions that in this case reflect new aspects of domestication, without leading to the dogs we know as dogs today.”
A paper The findings were published on November 24 in the magazine Proceedings of the National Academy of Sciences.
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Linus Girdland-Flink etc.. 2025. Gray wolves in an anthropogenic context on a small island in prehistoric Scandinavia. PNAS 122 (48): e2421759122; doi: 10.1073/pnas.2421759122
