Adult–adult play in captive lowland gorillas (Gorilla gorilla gorilla)

Abstract

Among African great apes, play is virtually absent between adult lowland gorillas (Gorilla gorilla gorilla). Here, we report an extremely rare case of adult–adult play observed in the lowland gorilla group housed at La Vallée de Singes (France). We recorded three playful interactions between the silverback and an adult lactating female. Given the diverse causal and functional nature of play, different factors may join in promoting this behaviour. In our group, contrary to what has been shown by previous studies in wild and captive gorillas, adult females spent more time in spatial proximity with the silverback than with other females. Hence, the probability of social interaction (including play) between silverback and adult females was enhanced. Moreover, the motivation of the lactating female to play might be an effect of oxytocin, a hormone that reaches high concentration levels during lactation and that promotes social affiliation. The fact that play invitations were always performed by the female might support this hypothesis. Certainly, we cannot exclude the possibility that the play event is a group idiosyncrasy or an artefact of captivity, even though the subjects never showed abnormal behaviour. Structurally, play sessions showed a suitable degree of pattern variability and switching frequency from one pattern to another. The proportion of offensive patterns was higher in the female during play and in the male during aggression, which conforms to the role reversal play phenomenon. In conclusion, this report confirms that the absence of evidence is not the evidence of absence. It is likely that under particular physiological or socio-ecological conditions, adult–adult play may be manifested as an “unconventional” part of gorilla social behaviour.

Object Play as a Positive Emotional State Indicator for Farmed Spotted Paca (Cuniculus paca)

“…In our study, we observed a reduction in agonistic behavior during the boomer ball phase compared with the control phases, as we predicted. Studies involving other species have also reported a decrease in aggressive behavior during object play behavior (e.g., Pan paniscus and Pan troglodytes [ 56 ]; Tursiops truncates [ 57 ]), while social play in adult animals can increase at times of social tension and high aggression risk (e.g., [ 58 , 59 ]). In our study, we provided one boomer ball per paca to allow access for all animals, thus minimizing potential resource disputes, although sometimes the pacas chased and tried to take the boomer ball from each other.…”

Diversity of play behaviour among mammals

“…Primates -Play "give me five" -dwa osobniki bawią się twarzą w twarz, uderzając się nawzajem po spodniej powierzchni dłoni (Cordoni i współaut. 2022).…”

“…-Play piggy back ride -osobnik ujeżdża drugiego, siedząc na jego plecach, z nogami trzymanymi okrakiem z jego boków i wyprostowanym tułowiem (Cordoni i współaut. 2022).…”

Is it for real? Structural differences between play and real fighting in adult chimpanzees (Pan troglodytes)

“…Even though play fighting is more frequent in immature individuals, in some primate species it is also retained and variably expressed in adulthood (e.g., Propithecus verreauxi-sifakas, Antonacci et al, 2010; Pan paniscus-bonobos, Palagi, 2006; Pan troglodytes-chimpanzees, Yamanashi et al, 2018; Gorilla gorilla gorilla -lowland gorillas, Cordoni et al, 2022b). For example, in bonobos play fighting is maintained at relatively high levels between adults .…”

“…Play fighting can be affected by individual (e.g., species, age, gender, and neural traits), social (e.g., affinitive and dominance relationships), and environmental (e.g., food abundance and predator presence) factors (Fagen, 1981; Pellis & Pellis, 2017). Even though play fighting is more frequent in immature individuals, in some primate species it is also retained and variably expressed in adulthood (e.g., Propithecus verreauxi —sifakas, Antonacci et al, 2010; Pan paniscus —bonobos, Palagi & Cordoni, 2012; Palagi, 2006; Pan troglodytes —chimpanzees, Yamanashi et al, 2018; Gorilla gorilla gorilla —lowland gorillas, Cordoni et al, 2022b). For example, in bonobos play fighting is maintained at relatively high levels between adults (Palagi & Cordoni, 2012).…”