Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific developments and more.
In an ancient grave in what is now northwestern Argentina, a person was buried with a canine companion, but this animal companion was not a dog, according to new research. At the burial lay the skeleton of a species of canid that had once competed with dogs for human affection: a fox.
People and dogs have a long history. The relationship between the two species goes back tens of thousands of years. However, a new analysis of evidence from a Patagonian burial dating back about 1,500 years suggests a similarly close link between a hunter-gatherer in southern South America and the large extinct fox species Dusicyon avus.
Archaeologists originally discovered the nearly complete D. avus skeleton in 1991, buried next to a human at Cañada Seca, a site in northern Patagonia. There were no cuts on the bones, so the fox had not been eaten, Dr. Ophélie said. Lebrasseur, researcher at the Wellcome Trust Palaeogenomics and Bio-Archaeology Research Network at the School of Archeology at the University of Oxford in the United Kingdom.
An in-depth analysis of ancient DNA and radiocarbon dating confirmed the species and age of the fox, and examination of collagen in the fox’s remains revealed that it ate the same food as this group of people. Together with the skeleton’s placement in the grave, the animal’s diet suggested the fox was tame and possibly kept as a pet, scientists reported Wednesday in the journal Royal Society Open Science.
The discovery adds to a growing body of evidence from cemeteries on other continents that suggests individual foxes were tamed by humans and shared a bond based on companionship.
The fox and hunter-gatherer society
D. avus lived from the Pleistocene (about 2.6 million to 11,700 years ago) into the Holocene, becoming extinct about 500 years ago. He was about the size of a modern German Shepherd, but much less bulky, weighing as much as 30 pounds.
“In general, Dusicyon avus has a carnivorous diet,” says Lebrasseur, who conducted the study with Dr. Cinthia Abbona, a researcher at Argentina’s National Scientific and Technical Research Council, led. But when the scientists tested the fox skeleton from the burial, they found that the diet was less carnivorous than expected, and more similar to the diet of humans.
“That suggests that the community was feeding the food, or it was around the community feeding on the kitchen waste,” Lebrasseur told CNN. “It would suggest that there is a closer relationship and integration of the canids into society.”
The idea of foxes as pets in South America is consistent with evidence from other fox burials in Europe and Asia, said Dr. Aurora Grandal-d’Anglade, a paleobiologist at the Universidade da Coruña in Spain. Grandal-d’Anglade, who was not involved in the new research, previously described Bronze Age graves on the Iberian Peninsula, with dozens of dogs and four foxes buried next to people. Researchers found that the foxes were arranged similarly to the dogs, suggesting that they too were companions for humans.
“There is no reason why foxes cannot be domesticated,” Grandal-d’Anglade told CNN in an email. “We know that in many very different societies, people often keep pets (not just canids, but monkeys, birds, reptiles, for example) simply as companions. Viewed in this light, more and more places appear where foxes appear to have played the role of companion animals.”
Finding D. avus in a human grave was surprising for another reason: Although the species was once widespread in southern South America, it was previously unknown in this part of Patagonia. Hunter-gatherers living in the region typically stayed within a radius of about 45 miles, so they likely encountered the friendly fox within that range, according to the study.
“The Dusicyon avus must be part of the immediate environment to be integrated into the community,” Lebrasseur said.
What Fox Burials Reveal About ‘Man’s Best Friend’
The analysis also shed light on what drove the foxes to extinction – or more accurately, what didn’t. One hypothesis suggested that the foxes interbred with dogs that European settlers had introduced to South America, and that interbreeding eventually caused the foxes’ lineage to become extinct. But the fox’s DNA told a different story, the study authors reported.
“Based on what we were able to find out and the technique we developed a few years ago in Oxford, we were able to suggest that hybridization between domestic dogs and Dusicyon avus could not produce fertile offspring,” Lebrasseur said.
However, it is still possible that dogs were not entirely innocent of the foxes’ decline. With a similar diet to D. avus, dogs may have helped accelerate the foxes’ extinction by outcompeting them. Dogs may also have carried and transmitted diseases that sickened the foxes, Lebrasseur added.
Experts often explain the domestication of dogs as something that happened because people realized they could put dogs to work as hunters or herders, Grandal-d’Anglade said. But the D. avus skeleton at Cañada Seca and other fox burials indicate that an animal did not have to be a useful worker to be cared for by humans; it could just be a friend.
“The proliferation of canids of different species in close relationship with humans seems to indicate that it was basically a relationship of affection and companionship,” Grandal-d’Anglade said. “The fact that we find them in so many different societies and on different continents indicates that keeping animals for companionship, and not just as working or meat animals, is an ancestral trait of humans.”
Mindy Weisberger is a science writer and media producer whose work has appeared in the magazines LiveScience, Scientific American, and How It Works.
For more CNN news and newsletters, create an account at CNN.com