Unveiling the “secret” of play in dogs (Canis lupus familiaris): Asymmetry and signals.

Abstract

Due to their playful propensity, dogs are a good model to test some hypotheses about play dynamics (length, asymmetry, features of players) and communication (play bow [PBOW]; relaxed open-mouth [ROM] display). We video-recorded 203 play sessions between dogs in an off-leash dog park in Palermo, Italy. Contrary to the expectation, play asymmetry (particularly high in this species) did not differ between stranger and familiar dogs, thus suggesting the limited role of play in forming dominance relationships. Asymmetry negatively affected the duration of the session, whereas the increasing number of players was positively linked to the duration of playful interactions. The number of PBOWs exchanged by players may exert a certain influence on the session length as well. PBOWs were performed independently from the kind of play (locomotor vs. contact) the dogs were engaging in. Conversely, ROMs were preferentially emitted during contact play when "face-to-face" interactions were more likely. Body closeness is also required in case opening the mouth has not a signal function but only preludes a bite. However, in the 82% of cases play bites did not follow a ROM, thus suggesting that dogs place ROMs in the appropriate context to optimize signal detectability. In conclusion, 2 tactics may concur in coping with the asymmetry and unpredictability of play sessions in dogs. First, whenever the asymmetry increases dogs shorten the duration of their sessions thus limiting the risk of possible escalation. Second, dogs make use of a good communicative system based on the reciprocal exchange of playful signals. (PsycINFO Database Record

Dogs and humans respond to emotionally competent stimuli by producing different facial actions

“… 35 ). To date, functional facial expressions in dogs have been largely discussed holistically in relation to their approach-avoidance value, for example, the “threat gape” in fight-flight situations 3 , and the PF or the Relaxed Open Mouth (ROM) as a social communicative signal for play solicitation and within play bouts 3 , 36 , 37 . With the development of the FACS for the domestic dog 24 , it becomes possible to apply a bottom-up technique to investigate the composition and meaning of dogs’ facial expressions and, more importantly, to establish possible analogies with humans, with whom they socially interact.…”

What is play fighting and what is it good for?

“…A first attempt to characterize turn taking in play fighting was the 50:50 rule (Altmann, 1962), which implies that, for play fighting to remain playful, the animals have to have equal chances of gaining the advantage (Dugatkin & Bekoff, 2003). Subsequent empirical studies have shown that play fighting can be substantially asymmetrical and still remain playful (Bauer & Smuts, 2007;Cordoni, Nicotra, & Palagi, 2016;Pellis, Pellis, & McKenna, 1993), although not if one partner completely dominates the interactions (Suomi, 2005;Wilmer, 1991). Thus, although the degree of reciprocity, or turn taking, can vary markedly with the species, age, sex, and dominance status of the participants (e.g., Bauer & Smuts, 2007;Biben, 1998;Cordoni & Palagi, 2011;Pellis et al, 1993), at least some degree of reciprocity is needed to sustain play (Bekoff, 2014;Palagi, Cordoni, Demuru, & Bekoff, 2016), and this is true whether the play fighting is derived from sex or aggression (Pellis & Pellis, 1988a, 1988bReinhart et al, 2010).…”

Differences in play can illuminate differences in affiliation: A comparative study on chimpanzees and gorillas

“…A play session is the outcome of cooperative and competitive elements that can be measured and quantified [ 22 , 23 ]. The way the session is built up is predictive of its function (for review [ 12 ]).…”

“…The short-term adaptive functions of play can be related to the level of cooperation and tolerance of the species considered [ 24 ]. For example, adult play rates generally covary with the level of tolerance and social affiliation characterizing the group (ungulates, [ 25 ]; rodents, [ 26 ]; canids, [ 22 , 27 ]; primates, [ 28 , 29 ]). Inter-individual tolerance favors the retention of play also during the adult phase, thus suggesting that this behavior can provide benefits also during adulthood [ 10 , 30 ].…”