Wolves, the wild ancestor of dogs, are the only large carnivores that have undergone domestication by humans. Yet, it remains unclear if this process took place via direct and deliberate human control of wild wolves or if wolf populations gradually adapted to the human niche. Now, archaeologists have unearthed the remains of two canid individuals with gray wolf genetic ancestry in the Stora Förvar cave on the Swedish island of Stora Karlsö in the Baltic Sea. This island is small (2.5 km2) and, like the neighboring island of Gotland, carries no endemic populations of land mammals, meaning that any such animals must have been brought there by people.
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 ancestry indistinguishable from other Eurasian wolves, but they seemed to be living alongside humans, eating their food, and in a place they could have only have reached by boat.”
“This paints a complex picture of the relationship between humans and wolves in the past.”
The genomic analysis of the two canid remains from the Stora Förvar cave confirmed they were wolves, not dogs.
However, they exhibited several traits typically associated with life alongside humans.
Isotope analysis of their bones revealed a diet rich in marine protein, such as seals and fish, aligning with the diet of the humans on the island and suggesting they were provisioned.
Furthermore, 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 the conventional understanding of wolf-human dynamics and the process of dog domestication.
While it remains unclear if these wolves were tamed, kept in captivity, or managed in some other way, their presence in a human-occupied, isolated environment points to 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 environments, humans were able to keep wolves in their settlements, and found value in doing so.”
“The genetic data are fascinating,” 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.”
“This is similar to what you see in isolated or bottlenecked populations, or in domesticated organisms.”
“While we can’t rule out that these wolves had low genetic diversity for natural reasons, it suggests that humans were interacting with and managing wolves in ways we hadn’t previously considered.”
One of the wolf specimens, dated to the Bronze Age, also showed advanced pathology in a limb bone, which would have limited its mobility.
This suggests 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 revealed new and very unexpected perspectives on Stone Age and Bronze Age human-animal interactions in general and specifically concerning wolves and also dogs,” said Stockholm University’s Professor Jan Storå.
“The study suggests that human-wolf interactions in prehistory were more diverse than previously thought, extending beyond simple hunting or avoidance to include complex relations and interactions that, in this case, mirrors new aspects of domestication without leading to the canines we know as dogs today.”
A paper on the findigns was published November 24 in the Proceedings of the National Academy of Sciences.
_____
Linus Girdland-Flink et al. 2025. Gray wolves in an anthropogenic context on a small island in prehistoric Scandinavia. PNAS 122 (48): e2421759122; doi: 10.1073/pnas.2421759122
