Why Do Dogs Play?

A new paper finds there are many reasons why dogs play – and play is not always a sign of good welfare.

There’s nothing cuter than watching puppies play together. But why do they do it? It turns out play has several functions, not just one. A new review, by Rebecca Sommerville (Royal (Dick) School of Veterinary Studies, University of Edinburgh) et al, considers four theories about why dogs play, and finds evidence in support of three of them.

Rebecca Sommerville told me in an email,

“We found, by reviewing a large body of research, that play is not one type of behaviour – there are several types that each serve a different purpose. Despite popular belief, a dog playing is not necessarily a sign that everything is well. Playing alone can be a sign of boredom, whilst play with other dogs has potential to be one sided. Regular, real play between a dog and owner does not revolve around commands, and is important to strengthen their bond.”

Four theories of why dogs play

The paper looks at four different theories of why play has evolved in dogs.

One theory is that play helps puppies learn motor skills. If you look at what dogs do in play, they chase each other, roll around on the floor in play fights, mount, pick up objects with their mouth and tug, bite or shake them. Puppies learn how hard they can bite their playmates (acquired bite inhibition), and to play bow to keep the play going for longer. Through these play activities, they are learning real skills relevant to how to move their bodies, acquire food, and defend themselves in fights. The scientists say this theory explains a lot of things about play, but is not the full story.

Another theory is that play is training for unexpected things to happen: it’s through play that dogs know how to right their bodies when knocked off balance and how to cope when something surprising startles them. According to this theory, changes in the brain and in hormone levels during play help dogs learn how to cope with real-life stressors. This theory explains the fact that dogs like new toys but are cautious of new things that aren’t toys. It also explains the way dogs self-handicap during play and put themselves at a disadvantage; this can be seen as practising behaviour they may need later on as a way to defuse real aggression. But again, this theory only explains some aspects of play.

The third theory they found evidence for is the idea that play promotes social cohesion between dogs. Play helps dogs cooperate as a group, and is about building social relationships – in which humans also feature. Dogs prefer to play with people they know, and they are more likely to approach the winner of a game, but when they win a game against a person it does not lead to increased ‘dominance’. So play is about building cooperative relationships, not social rank. But again, this theory does not explain everything about play.

The fourth theory the scientists considered is that play is just a side-effect of other processes, such as having too much energy or a deprived environment that does not provide stimulation. However, poor environments are linked with the development of stereotypies (repetitive behaviours), rather than play. If play was linked to too much energy, then playfulness wouldn’t be a consistent trait in dogs. Because play is something humans like, it may have been selected for in domestication or have arisen as a result of breeding for other traits, such as neotenic (baby-like) features. But play does not seem to just be a by-product of other things.

Play and welfare in dogs

There is an increasing emphasis on positive welfare and so the paper also considers the welfare implications of different types of play. Individual play with toys is an important enrichment activity that is rewarding in its own right and may reduce stress, but in some cases it may reflect poor welfare (e.g. poor environment, not enough attention from humans).

The scientists say that social play with other dogs is good for canine welfare, although there may be risks of injuries if play turns into aggression. Dogs that do not get enough play opportunities when they are young may show inappropriate behaviour in adult play with dogs or humans. If it is misinterpreted by the owner as actual aggression and the dog is given fewer play opportunities as a result, this may lead to reduced welfare.

Photos: Natalia Fedosova; top, Johan Georg Theron. Both Shutterstock.

Finally, dogs also like to play with humans, and would prefer to play with a human than on their own when there is a toy around. The scientists distinguish between indirect play (when the human moves a toy for the dog – playing with a flirt pole would be an example) and direct play when the human and dog are directly playing together. Play with humans can be rewarding in itself and may also improve the human-canine bond.

However, there are also times when play with a human may not be a sign of good welfare: when dogs make a playful move as a way of avoiding something unpleasant from the human, or in cases where the play itself is stressful, as has been found for games of tug that are also full of commands and discipline rather than being spontaneous and affectionate.

The researchers say that although several studies have looked at different types of reward in dog training, research is needed on the use of play as positive reinforcement. They say that using play to promote the adoption of shelter dogs is another example of using play to improve welfare.

So why do dogs play?

Ultimately, dogs play because it helps them learn motor skills, build social cohesion and prepare for unexpected things to happen so they can cope better when they do. Different stages of play may have different functions, with the beginning and end of a play bout especially important for social cohesion, while the main part of play is most important for learning motor skills and preparing for the unexpected.

"Regular, real play between a dog and owner does not revolve around commands,

and is important to strengthen their bond.”

The review did not find evidence for the idea that play is simply a side-effect of other processes. But it did find that play per se is not necessarily a sign of good welfare; in some cases, it may indicate welfare issues.

The scientists also say that other possible reasons for play need more research, such as whether or not it helps with cognitive development or coping with stress.

This is a fascinating paper. The idea that play is multi-faceted and was probably selected for in domestication is also supported by Bradshaw et al’s (2015) review of play behaviour in adult dogs. I look forward to seeing a lot more research on how and why dogs play!

What does it mean for your dog?

Although the paper does not specifically consider the implications for dog owners, there are some things to bear in mind.

Play fulfils several important functions. So next time you see puppies playing, remember it’s not just fun – they are practising useful skills and building social relationships.

It can be hard for people to find suitable (safe) playmates for new puppies, so a good puppy class should include opportunities for play. This will help your puppy to develop useful skills for later in life. Play should be a positive experience, so expect the dog trainer to monitor it carefully. If at any time you are not sure if your puppy is enjoying it, do a consent test: separate the puppies and see if they both want to return to play or not.

Remember that puppies coming from commercial breeding establishments may not have had many play opportunities with their littermates because of the environment in which they are raised (see: potential causes of problems in pet store puppies). In this case, it may be even more important to have play sessions during puppy class so they can learn appropriate canine social skills. (Note that puppy class is just for puppies, not adult dogs, because of the risks of infection and in case the adult dogs are not well socialized).

If you have one of those adult dogs who is lacking in play skills or bullies other dogs, a good dog trainer will be able to help. Kristi Benson CTC explains how to improve play skills here. Since dog training is not regulated, make sure you find a good dog trainer.

Of course the main take-away for dog owners is that it’s important to play with your dog because it helps to strengthen the human-animal bond.

You can follow the first author, Rebecca Sommerville, on twitter.