Playing a game of fetch with a dog means they are following a human social cue to recover the ball. But fetch isn’t just for dogs, wolf puppies are down to play too, which means they can also understand human communication cues, according to a new study.

The findings, published in the journal iScience, were made after researchers put 13 8-week-old wolf puppies from three different litters through a series of tests usually used to assess dog-puppy behavior. Three of the pups were interested in playing fetch with a stranger, which included bringing a ball back when encouraged to.

The discovery was quite a surprise for the team as it was believed that the cognitive abilities necessary to understand communication cues given by a human were presented in dogs only after humans domesticated them 15,000 years ago. Dogs differ from wolves physically, genetically and behaviorally.

“When I saw the first wolf puppy retrieving the ball, I literally got goosebumps,” said Christina Hansen Wheat of Stockholm University in a press release. “I immediately knew that this meant that if variation in human-directed play behavior exists in wolves, this behavior could have been a potential target for early selective pressures exerted during dog domestication.”

Wanting to learn more about the effects of domestication on behavior, Hansen Wheat and her team raised wolf and dog puppies from the age of 10 days and put them through various behavioral tests. In one of them, the pup was thrown a ball by an unknown person, encouraging the wolf to get it and bring it back.

Expectations of the wolf pups catching on weren’t high, with the first two litters showing no interest in the balls, let alone of playing fetch. But everything changed with the third litter. A few of the puppies went for the ball and even responded to the social cues and brought it back.

“It was very surprising that we had wolves actually retrieving the ball,” said Hansen Wheat. “I did not expect that. I do not think any of us did. It was especially surprising that the wolves retrieved the ball for a person they had never met before.”

In the past, other research showed that domesticated and non-domesticated species will follow human gestures if a food reward is given, Hansen Wheat and her team said. But in those cases, the animals were previously trained to follow the cues or knew the person conducting the study.

While the new research has a limitation over the size of its sample, it could reassess our interpretation that understanding human social cues came from domestication. Instead, it could be possible that this behavior can be traced back to an ancestral population before wolves were domesticated into dogs.