“[These results] should encourage the scientific community to reexamine the hypotheses about the purpose of domestication,” says Kira Cassidy , a wolf research at Yellowstone National Park who was not involved in the study. “[While] wolves have evolved to cooperate in order to survive...perhaps, after many generations of domestication, dogs now see humans as their family.”

So far, these differences have only been noted with dogs raised in packs, and can’t be extrapolated to any pooches that live as pets. But the results hint at a surprising possibility: To become humans’ best friends, dogs may have had to reroute their loyalties—and snub their own species in the process.

According to a study published today in the journal PLOS ONE , wolves appear to be more inclined than dogs to be generous with their pack mates. When given the choice, wolves deliver food to their friends, even if they don’t benefit themselves. Dogs, on the other hand, quickly lose interest in the absence of personal payoff.

Given the choice between a wolf and a dog for a companion, you might be more inclined to choose a floppy-eared mutt.

To suss out whether dogs or wolves had the upper paw, a team of researchers led by Rachel Dale decided to see if two groups of canines would be willing to perform the ultimate act of altruism: give without getting in return.

Dogs’ persisting partnership with people may make it tempting to give humans all the credit for canine congeniality. But gray wolves, the other direct descendants of that long-gone lupine ancestor, aren’t exactly slouches at cooperation. In the wild, wolves rely on their pack mates for everything from food to caring for their young. The charitable nature of domestic dogs may be a product of human intervention—but it could just as easily be an age-old trait passed down from their pack-living predecessors.

All domestic dogs can trace their genetic roots back to a fierce, wolf-like ancestor—but today, few dog breeds still look or act the part. Over the course of human-driven domestication, this once-wild lineage grew tame, eventually accumulating enough genetic changes that an entirely new species arose. Now, modern mutts lounge in our living rooms and nibble at scraps from the edges of our plates; they’ve even learned to tune in to the subtleties of human emotion .

But the cushy, human-centric lifestyle of pet dogs can be hard to compare to the the close-knit, pack culture of wolves. To level the playing field, Dale and her team conducted their experiments using captive wolves and dogs raised in cohorts of their own species at the Wolf Science Center in Austria.

Nine wolves and six dogs were given the opportunity to deliver a tasty treat to a pack mate by pressing their noses to a “giving” symbol on a touchscreen. (To make sure the wolves weren’t just having fun nosing the touchscreens, the researchers also included a “withhold” option on the interface.) None of the donors were able to access the food themselves, but if they behaved selflessly, they could watch their friends chow down in their place.

To Dale’s surprise, the wolves repeatedly bested their domestic canine cousins in the realm of generosity. While the wolves booped the “giving” option time and time again to reward their pack mates, dogs were less likely to be team players.The wolves also showed an obvious preference for familiar faces, quickly losing interest in the tasks when they didn’t recognize the recipient. Dogs, on the other hand, didn’t seem eager to gift grub to other members of their species, regardless of whether they’d spent time with them or not.

These results were “surprising at first,” but in hindsight, there are several reasonable explanations, says Julia Meyers-Manor, a dog behavior expert at Ripon College who was not involved in the study. In the wild, teamwork is often a matter of life and death—but within the cozy confines of human civilization, independence might be a more useful strategy. As dogs exchanged a lifestyle of hunting for scavenging human scraps, there may have been less pressure for groups of canines to act as cohesive units, and instead fend for themselves.

Because the wolf on the right pressed the "giving" symbol, its partner on the left was rewarded with a piece of sausage while the donor watched. Image Credit: Rachel Dale, Wolf Science Center

“Domestication hasn’t necessarily made dogs more tolerant of, or cooperative with, each other,” Dale says. “Some people have assumed this…but just because they’ve been selected to work so well with humans, that doesn’t mean they’ll do it with each other as a byproduct.” In fact, Dale says, it’s possible that the inverse may be true: Through domestication, humans could have inadvertently encouraged canines to choose person over pup.

For now, that’s still a theory. Additionally, because the dogs in the study grew up in packs, the results don’t have any bearing on how pet dogs, which spend most of their time around humans, might behave. In fact, Dale’s previous work suggests that dogs raised in the presence of people will happily share resources with their own kind.

It’s not yet clear why dogs may differ as pets or pack mates, but Dale has a theory. While pack dogs live by their own set of rules, most of the mutts that hang out with humans are rewarded for being chummy, she says. That sort of positive reinforcement could bring out the best in these dogs under all kinds of circumstances.

In other words, there’s nothing to show that dogs have lost the ability to lend a helping paw. After all, plenty of canines can still be counted on to have each other’s backs—and they were doing it long before we humans entered the picture.

“Sometimes we think, ‘Humans can cooperate, and it’s something other animals don’t have,’” says Gitanjali Gnanadesikan, who studies social behavior in dogs at the University of Arizona, but was not involved in the study. “But we see examples of this behavior throughout the animal kingdom...it’s naive to think other animals wouldn’t have ways of collaborating.”