1. The Function of Play Bows in Dyadic Dog Play
S. Byosiere & B. Smuts
Today I’m going to report on my masters thesis which is an ongoing study of play bows at the university of Michigan with Barb Smuts.

2. However, before I begin I would like to show you what this behavior looks like within a dyadic canine interaction.

3. Research Question • What is the function of the play bow?
Because this behavior is quite noticeable and stereotyped across canids, we attempted to understand its function.

4. Bekoff (1995)
• Subjects: Infant canines, infant wolves, and infant coyotes
• Pairwise play encounters during ages 3-7 weeks.

5. Bekoff (1995) – Results
Percentage of behaviors immediately after different behaviors in infant dogs.
Action Before
Percentage of Bows Following the Behavior
Bite-shake
11.0
Bite w/o shake
1.4
Mouthing
1.5
Standing over
1.8
Bekoffs results highlighted a specific behavior called the bite shake in which.. He looked at how often play bows occurred after different behaviors. He found that bows were significantly more likely to occur after bite shake behaviors than any other of the behaviors large enough to be included in the analysis.

6. Bekoff (1995) – Conclusions
In canids, bows are significantly more likely to occur right after behaviors that can easily be misinterpreted as aggression.
Therefore, Bekoff concluded that play bows function to communicate playful intent to avoid escalation of actual aggression.
However, this hypothesis needs to be tested further. Other studies show that bite shakes are non-existent in adult dogs.
Bekoffs results suggested that play bows function to clarify easily misinterpretable behaviors, specifically behaviors that could be misinterpreted as aggression. Results for dog puppies are what we will focus on, although the results were fairly similar across all canids.
Its possible that play bows function in adult dogs in the same way but reference different attack behaviors other than bite-shakes, or play bows may function differently.

7. Hypotheses
Play bows function to communicate playful intent when most necessary.
Due to the scarcity of bite shakes in adult dog play, we adapted Bekoffs conclusion to adult dogs.

8. Hypotheses
Play bows function to communicate playful intent when most necessary in adult dogs.

9. Pellis and Pellis (1996)
Play bows function to increase maneuverability and obtain and optimal position.
Alternatively, Pellis and Pellis have set forth 2 hypotheses on the function of play bows. To our knowledge, these have not been tested.

10. Hypotheses
Play bows function to communicate playful intent when most necessary in adult dogs.
2a. Play bows function to position the dog to attack the play partner… and/or
Pellis and Pellis Hypothesis (1996)

11. Hypotheses
Play bows function to communicate playful intent when most necessary in adult dogs.
2a. Play bows function to position the dog to attack the play partner… and/or
2b. to position the dog to escape the play partner.
To evaluate these studies we tested these hypothesis.

12. Adult Dog Play Bow Study
14 adult domestic dogs
18 dyads
274 recorded play bows
Looked at 18 dyadic pairs, a total of 14 adult domestic dog interactions.

13. Behavior Categories
• Offensive: Chase/Charge, Push/Tackle, Nip, Bite, Forced down

14. Behavior Categories
• Offensive: Chase/Charge, Push/Tackle, Nip, Bite, Forced down
• Defensive: Run away, or being in defensive position

15. Behavior Categories
• Offensive: Chase/Charge, Push/Tackle, Nip, Bite, Forced down
• Defensive: Run away, or Being in defensive position
• Pause: Stationary positions

16. Behavior Categories
• Offensive: Chase/Charge, Push/Tackle, Nip, Bite, Forced down
• Defensive: Run away, or Being in defensive position
• Pause: Stationary positions
• Synchronous: Mutual rear up, Move together
• Miscellaneous: Close approach, Move away
Two other categories were created, but I will not address as they reflect different hypothesis.

17. Method of Analysis Before Bow After Bow Bower Partner
• General linear mixed model of behavior categories proportions over all other behavior categories.
Before Bow
After Bow
Bower
Partner
We conducted a general linear mixed model assessing the proportion of behaviors before and after by the partner and the bower. We addressed 4 comparisons, the bower before and after, the partner before and after, the bower and partner before, the bower and partner after.

18. Hypothesis 1
Play bows function to communicate playful intent when most necessary in adult dogs.
• If play bows are used to clarify easily misinterpretable offensive behaviors, like bite-shakes, the bower to show more offensive behaviors than the partner both before and after the play bow.
Before Bow
After Bow
Bower
Offensive
Partner
Not offensive
In order to test hypothesis one, that bows function to communicate playful intent when most necessary in adult play, we predicted that bowers would display aggressive behaviors than the partner both before and after the play bow. Since bite shakes are aggressive behaviors, this category would best represent easily misinterpretable aggressive behaviors. In addition, this would allow us to determine if adult dogs utilize other aggressive behaviors than the bite shake in association with play bows.

19. Hypothesis 1 • Bite shakes were never seen in all 274 play bows.
• Bites or nips were only seen 5% of the time.
• Play partners not play bowers were more likely to perform offensive actions than the bower (p=0.01) after the bow (p=0.0002).
Before Bow
After Bow
Bower
NOT OFFENSIVE
Partner
Not offensive
OFFENSIVE
But bite shakes were never seen. We therefore looked at other bite behaviors, and found that they rarely occurred in association with bows.
The general linear mixed model found that partners, not bowers were more likely to be offensive after the bow than before.

20. Hypothesis 1
• These results are opposite of those found by Bekoff (1995), therefore play bows seem to function differently in adult than infant play.

21. Hypothesis 2a
2a. Play bows function to position the dog to attack the play partner.
• If play bows are used to obtain an optimal position to better attack the play partner, the bower to show more offensive behaviors after the play bow than before.
Before Bow
After Bow
Bower
Not offensive
Offensive
Partner
In order to address our second hypothesis, that bows function to better attack the partner, we predicted that bowers should display more offensive behaviors after the play bow than before.

22. Hypothesis 2a
• Play bowers were more no more likely to perform offensive actions after the bow than before (p=0.9216).
Before Bow
After Bow
Bower
Not Offensive
NOT OFFENSIVE
Partner
But this was not the case. For bowers there was so significant effect of timing, meaning that they were equally likely to bow before and after the play bow.

23. Hypothesis 2b
2b. Play bows function to position the dog to escape the play partner.
• If play bows are used to obtain an optimal position to better escape the play partner, I expect the bower to show more defensive behaviors after the play bow than before.
Before Bow
After Bow
Bower
Not Defensive
Defensive
Partner
The second part of hypothesis two suggests that bows function to better escape the play partner. If so, we predicted that bowers would be more likely to display defensive behaviors after the play bow than before. The main reason for this hypothesis is that our closest code to “escape” was a runaway and was listed under this behavior category.

24. Hypothesis 2b
• Play bowers were more likely to perform defensive actions after the play bow than before (p<0.0001).
Before Bow
After Bow
Bower
Not Defensive
Defensive
Partner
And for this hypothesis we found support. Bowers were more likely to be defensive after the bow than before.

25. Hypotheses 2a, 2b
• These results fail to support the idea that bows are used to better attack the partner.
• These results support the idea that bows are used to escape the play partner.
In summation, we failed to find evidence that bowers were using play bows to better attack their play partners, however found support that bowers are utilizing defensive behaviors after the bow, perhaps to escape the partner.

26. Hypotheses
Play bows function to communicate playful intent when most necessary in adult dogs.
2a. Play bows function to position the dog to attack the play partner… and/or
2b. to position the dog to escape the play partner.
Thus hypothesis 2b seems to explain the function of play bows, however I would like to address a third hypothesis we decided to test as well.

27. Hypotheses
Play bows function to communicate playful intent when most necessary.
2a. Play bows function to position the dog to attack the play partner… and/or
2b. to position the dog to escape the play partner.
3. Play bows function to initiate or re-initiate play after a pause.
And that is that play bows function to initiate or re-initiate play after a pause.

28. Hypothesis 3
3. Play bows function to initiate or re-initiate play after a pause.
• If play bows function to reinitiate play, I expect the bower and the partner to display more pauses before the play bow than after.
Before Bow
After Bow
Bower
Pause
Active Play Behavior
Partner
If this is the case, bowers and partners should be more likely to display pause behaviors before the bow than after. Reciprocally this means they were more likely to show active behaviors after the play bow.

29. Initiation and Re-initiation of Play
• Both bowers and partners were more likely to display pause behaviors before the play bow than after (p<0.0001).
Before Bow
After Bow
Bower
Pause
Active Play Behavior
Partner
And this is exactly what we found. Bowers and partners were significantly more likely to display pause behaviors before the bow and active behaviors after.

30. Hypothesis 2b or 3?
• What behaviors are bowers and partners actually using most frequently before and after play bows?
We now have support for hypothesis 2b and hypothesis 3. So which is it? Both of these could be true, but lets look at the most common behaviors right before and after play bows.

31. Hypothesis 2b or 3? Most Common Before Behavior
Most Common After Behavior
Bower
Relatively Stationary
(40.07%)
Runaway
(24.18%)
Partner
(39.3%)
Chase
(18.4%)
For the bower, the most common behavior before the bow was relatively stationary, one of the pause behaviors. 40% of the time doing ther bower and partner are simply standing around before the bow. 25% of the time the bower takes off and runs away, so is this in fact an escape as pellis and pellis have suggested or potentially something else. If you look at the partners behavior after the bow, the most common behavior performed is a chase, a complimentary behavior to the runaway.

32. These results suggest that the runaway performed by the bower, rather than being associated with an attempt to get away from an attack by the partner, more likely is an attempt to initiate play by enticing the partner into a chase.

33. 3. Play bows function to initiate or re- initiate play after a pause.
Hypotheses
Play bows function to communicate playful intent when most necessary.
2a. Play bows function to position the dog to attack the play partner… and/or
2b. to position the dog to escape the play partner.
3. Play bows function to initiate or re- initiate play after a pause.
Most common function of play bows in adult dogs is to reinitiate play after a pause.