Wolf pups versus dog pups: Nurture can’t overpower nature, Duke researchers find

When you throw a ball for your dog to fetch, they’ll understand almost immediately. A new Duke University-led study has shown that a wolf probably wouldn’t.

To begin the study, 37 wolf puppies at the Wildlife Science Center in Minnesota interacted with humans nearly 24/7 just days after they were born — they were fed by hand and even slept in the same beds as their caretakers. Meanwhile, 44 dog puppies from the Canine Companions for Independence program at Duke lived with their mother and litter mates but did not have as much contact with humans.

Tests demonstrated that wolf and dog puppies perform nearly equally in almost all areas, but when it came to social cognition, dog puppies were much more likely to interact with and understand humans.

Dog puppies much more likely to approach people

One series of tests showed that dog puppies were over 30 times more likely to approach a stranger and five times more likely to approach a familiar person compared to the wolf puppies.

Hannah Salomons, a doctoral student at Duke, said that while she expected this trend, she was surprised by the magnitude of the results.

“Even just anecdotally, interacting with the wolf puppies is so much different than interacting with the dog puppies,” Salomons said in a press release announcing the results of the study. “You can really tell right away when you go into a pen of dog puppies versus a pen of wolf puppies. It’s such a different experience.”

Dog puppies would climb on researchers and lick their faces if they walked in the enclosure, Salomons said. The wolf puppies would run to a corner and hide.

“It makes a lot of sense because sadly, there’s only a few hundred thousand wolves left in the whole world. The ones that are left, of course, are the ones that are fearful and hide and run away,” said Brian Hare, a senior author of the study and professor of evolutionary anthropology at Duke.

Dog puppies better understood communicative gestures, eye contact

For the social tests, the researchers presented the puppies with two bowls, one of which had a treat hidden inside. They then gestured or pointed at the bowl in which the food was hidden and let the puppy choose which bowl to approach.

Salomons said the puppies might have seen a pointing gesture before because they’d already spent time around people. To account for this, for some puppies, they placed a wooden block by the bowl with the treat and let the puppies make the choice.

She mentioned that they included a couple controls in the experiment to make sure the puppies weren’t just sniffing the human hand or treat.

Despite being raised with limited human contact, 17 of the 31 dog puppies consistently approached the right bowl, compared to none of the 26 wolf puppies.

To test eye contact, the researchers put food in a closed, clear container so that the puppies could see it but not open it. They measured how much eye contact the puppy made with the experimenters and found that the dog puppies made more eye contact on average than the wolf puppies.

“You can interpret that as they were looking to the person for information or for help,” Salomons said.

Wolf and dog puppies equal in memory, impulse control

The dog and wolf puppies performed about equally in all the non-social cognitive tests, such as motor impulse control and memory.

To test impulse control, the researchers put a clear cylinder between the puppies and food. The puppies’ instinct was to go straight, but they’d bump into the wall. The researchers tracked how many attempts it took the puppies to learn to go around the cylinder to get to the food.

How is it that despite being surrounded by humans constantly, the wolf puppies still underperformed compared to the dog puppies? The results of the study weren’t due to experience — dog puppies were born with a more friendly temperament due to generations of domestication by humans.

“We find that that kind of selection [for a friendly temperament] during domestication resulted in dogs having this really early emerging ability to understand social gestures,” Salomons said. “So it’s not only that they can learn it throughout their lifetime: they’re actually born kind of prepared to be able to follow those social cues really easily.”

Wolf puppies may be able to learn these cues throughout their lives, but it would require a lot of training.

“If you’re going to have a wolf that cooperates and communicates as an adult, then that wolf is probably going to have to have a lot of experience with humans and really explicit training to reach the level that dogs can reach just naturally,” Hare said. “It’s just part of [dog puppies’] nature to communicate and be attracted to us.”

Who’s smarter?

According to Hare, the question of which animal is smarter is like asking if a hammer is a better tool than a screwdriver.

“They’re each designed to solve a certain set of problems, and they’re really, really good at solving the problem they’re designed for,” he said.

For example, wolves showed to be better at cooperating with each other to solve problems, like finding food together. Dogs had much better cooperative, communicative interaction with humans. This pattern makes sense considering that wolves often hunt and scavenge together, while dogs rely on humans to feed and care for them.

What’s next

Salomons and Hare agreed that the next step for this research would be to see how the pups’ cognition and temperament interact with each other and develop over time. The researchers are going to follow individual puppies from eight to 20 weeks old and run the series of tests every two weeks.

“Now, we can kind of see within individual puppies and over the course of their development, how are these skills developing? Are social skills emerging before non-social skills? Are they necessary for some of the other skills to emerge? And we’ll see how they all interact with one another,” Salomons said.