Wednesday, 22 February 2017

The Function of Play Bows in Dog and Wolf Puppies

New research casts doubt on an old explanation for the play bow – and suggests it’s all about more play.

A Border Collie does a play bow in the snow


The play bow is a glorious signal in dogs. The bum goes up and the elbows go down, leaving the rear end sticking up, usually accompanied by a lovely happy face (as pictured above). Not just reserved for other dogs, our canine friends will play bow to us too.

Traditionally, it was believed that the play bow serves as a signal to say something like, “I’m just playing, it’s not real!”, because many of the behaviours dogs perform in play – chasing, growling, biting, nipping, etc – can also be aggressive. But recent research with adult dogs has thrown that into question.

In 2016, Sarah-Elizabeth Byosiere (University of Michigan), Julia Espinosa and Barbara Smuts looked at play bows between adult dogs. If the play bow functions to say “I’m only playing!” then you would expect to see more ‘offensive’ behaviour that could potentially be misinterpreted either just before or just after the play bow. They did not find this. Instead, both the bower and the bowee were typically still before the play bow happened. Afterwards play resumed in the form of chase sequences or both dogs rearing up.

In other words, the play bow seemed to function as a signal to make play start again after a pause.

Byosiere et al concluded,
“the fact that both bowers and partners were often stationary before play bows and highly active after them (in the form of synchronous interactions or runaway/chase dynamics) supports the hypothesis that bows most often functioned to reinitiate play after a pause.”
But that study only looked at adult dogs. And in fact, dogs are not the only animal that play bows: coyotes, foxes, lions and wolves have all been seen to play bow. A new study by Byosiere et al investigates the role of play bows for dog and wolf puppies.

All of the puppies in this study were hand-reared, which means that the dogs and wolves have all grown up in a similar environment. The wolf pups were born in captivity and hand-reared in small groups; and the dog puppies were born in an animal shelter in Hungary and also hand-reared in the same way as the wolves.

The study analysed videos of dog-dog and wolf-wolf play in which at least one of the dogs or wolves was a puppy. The researchers coded play bows that were performed by the puppies during a play bout. The dog puppies were 2 – 5 months old, and the wolf puppies were 2.7 to 7.8 months.

It has been suggested before that the play bow is a visual communication signal, which means that it would be performed when the bower is in sight of the bowee. The results found this was the case, as previously found by Horowitz (2009).

A cute white puppy does a play bow outside
Photo: Cryber; top, xkunclova; below, Warren Metcalf (all Shutterstock.com)


In the wolf puppies, every one of the 69 play bows coded was performed while the two were in visual contact. In the dog puppies, all but one of the 136 play bows was performed in sight of the other dog. And in the one case where the other dog was not looking, the bowee barked, suggesting they knew they needed to get their partner’s attention.

As described for the adult dog study, if the play bow is a signal to say “I’m just playing”, you would expect to see more ‘offensive’ behaviour immediately before or after it. This was not the case for either wolf or dog puppies prior to the play bow. After the play bow, the dog partners (i.e. the bowees) showed more offensive behaviours, which is contrary to this hypothesis.

The scientists also looked specifically at bites, and found there were no bite-shakes immediately before or after the play bows. This is surprising, because earlier work by Bekoff (1995) found that play bows were associated with bite-shakes. The difference might be because Bekoff looked at younger puppies. In fact there were few bites and nips in the videos of dogs and wolves used in this study.

Another possible reason for a play bow might be so that the bower is well-placed either to run away from or chase the other dog. In Byosiere’s earlier study with adult dogs, there was no evidence of it being used to attack the other dog in play, but it seemed possible it was used to escape.

In fact for the dog puppies, their partner (bowee) was more likely to play-attack them than the other way around. This was not found in wolves.

Two young wolves playing in the snow


However, both wolf puppies and dog puppies were more likely to run away after the play bow, suggesting it positions them to escape.

As mentioned above, Byosiere’s study with adult dogs found that play bows tended to occur after a pause and serve to re-start play. This was the case for dog puppies, as both bower and bowee tended to be stationary before the play bow. In wolf puppies, however, this was not confirmed, although the bowees did tend to be still before the play bow.

Finally, it has also been suggested that play bows might serve to synchronize behaviours between the two partners after the bow. However, this was not found to be the case for either wolf or dog puppies.

The results of both studies are summarized in the table.

Dogs play bow in order to re-start play after a pause, science suggests
Reproduced from PLOSOne under Creative Commons Licence

The scientists write,
“Taken together, findings from this study and the previous study on adult dogs suggest that play bows do not occur at random and do not, therefore, simply enhance the play atmosphere in a general way. Instead, their association with particular behaviors before and after the play bow suggests strategic use of this play signal to accomplish immediate goals, including continuation of play by enticing the partner into a runaway/chase interaction.”
This study finds that the play bow is a visual signal for both dog and wolf puppies, but it does not serve to stop ‘offensive’ behaviours from being misinterpreted, as previously thought. In dogs, it seems to re-start play after a pause, however in wolf puppies the function is less clear. The authors suggest it may be that the intent is still to re-start play, but that it is less likely to be successful in wolves.

This is a fascinating study that will no doubt have many of us paying more attention to what happens before and after our dogs play bow.

The study of wolf and dog puppies is open access and can be read via the link below, while you can find the adult dog study via Sarah-Elizabeth Byosiere’s Researchgate profile.

What do you like about watching dogs play?

You might also like: Do hand-reared wolves get attached to their humans? and 6 reasons to love canine science.



References
Bekoff, M. (1995). Play Signals as Punctuation: the Structure of Social Play in Canids Behaviour, 132 (5), 419-429 DOI: 10.1163/156853995X00649
Byosiere SE, Espinosa J, & Smuts B (2016). Investigating the function of play bows in adult pet dogs (Canis lupus familiaris). Behavioural processes, 125, 106-13 PMID: 26923096
Byosiere SE, Espinosa J, Marshall-Pescini S, Smuts B, & Range F (2016). Investigating the Function of Play Bows in Dog and Wolf Puppies (Canis lupus familiaris, Canis lupus occidentalis). PloS one, 11 (12) PMID: 28033358
Horowitz A (2009). Attention to attention in domestic dog (Canis familiaris) dyadic play. Animal cognition, 12 (1), 107-18 PMID: 18679727
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4 comments:

  1. I'm following this research very closely, it's so fascinating :-)

    ReplyDelete
  2. Thanks for sharpening my observations of my dogs' behavior!

    ReplyDelete
  3. I am an admin for a blind dogs group and we find visual cues can be very difficult for blind dogs because, well, they can't SEE them! Finding solutions is tough.

    ReplyDelete

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