Social Play In African Savannah Elephants May Inform Selection Against Aggression

In social groups, competition for individual advantage is balanced with cooperation, for the collective benefit. Selection against aggression has favoured cooperation and non-aggressive competitive strategies. Because social play is a behavioural system that fluctuates between cooperation and competition, selection against aggression might have especially influenced this behaviour. African savannah elephants (Loxodonta africana) are a low aggressive species, therefore suitable to investigate this aspect. We collected all occurrences observational audio-video data on social play, aggression/threats, and affiliation on an African elephant colony housed in a 25-ha open space at Parque de la Naturaleza de Cabarceno (Cantabria, Spain) and composed of four family groups (3 immature males, 3 immature females, and 7 adult females) and two adult males. Anticipating the influence of reduced aggression, we found that social play decreased with age, persisting in adults, and that it was highest in males. Social play was associated with affiliation (informing cooperation). Indeed, individuals that were central in the social play network were also central in the affiliation network. For immature subjects, we found a correlation between social play and affiliation sociomatrices. However, such correlation was absent in adults and social play mostly occurred between families. Despite the limitations related to dealing with a small captive group, this study largely supports the idea that the features of social play in African savannah elephants may be related to low aggression. This investigation hints toward a non purely cooperative use of play, possibly as a non-aggressive interaction that accommodates different levels of cooperation and competition.