“Stop trying to make fetch happen” is probably what everyone said to researchers in Stockholm, who recently released a preprint describing a surprising feat: three wolf puppies spontaneously retrieving a thrown ball. Previously, play between species that is based on social-communicative cues — like when a human throws a ball and says “Fetch!” — was thought to be unique to dogs, but the 8-week-old pups, named Sting, Lemmy and Elvis, showed otherwise.

In this study, researchers brought in a “puppy assessor” to measure 13 wolf pups against the metrics used to describe the behaviors of dog puppies. During one of the test situations, the assessor, whom the wolves had never met, threw a tennis ball across a room, called the name of the wolf pup and encouraged it to bring the ball back. Over a course of three trials, Lemmy and Elvis responded to the assessor’s call and retrieved the ball twice, and Sting responded to the call and brought back the ball all three times. The other 10 wolf pups either played with the ball on their own or showed no interest in it.

Other than being what I imagine was an incredibly cute situation, this research fills in an important gap in our knowledge about how wolves evolved into dogs. Most scientists support the theory of self-domestication, in which the friendliest members of a species gain an evolutionary advantage (such as greater access to food or protection). Descendants of these super-friendly wolves eventually gained the traits we associate with pooches, like puppy-dog eyes and floppy ears. But for this kind of selection to take place, there would need to be pre-existing variation in wolf populations that made some pups friendlier than others. 

Though all dogs are good boys, Sting, Lemmy and Elvis might be examples of these intrinsically better (wolf) boys. 

Updated: January 16th, 2020

The research has now been published in the peer-reviewed journal iScience. Perhaps more importantly, we have videos of the wolf puppies playing fetch.

Here's Sting fully retrieving the ball! There are also videos of wolves playing with the ball but not retrieving it, a noticeably different response.

And for good measure, here is a photo of wolf pup Flea looking adorable after failing the fetch test: