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 favored cooperation and non-aggressive competitive strategies.Because social play is a behavioral system that fluctuates between cooperation and competition,selection against aggression might have especially influenced this behavior.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 4 family groups(3 immature males,3 immature females,and 7 adult females)and 2 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.

Witness for resolution: post-conflict quadratic affiliation in semi-free ranging pigs

In social mammals,post-conflict resolution can involve the reunion of former opponents(reconciliation),spontaneous/solicited post-conflict affliation of a third party with either opponent(triadic contacts),and affiliation between other individuals(hereafter bystanders;quadratic contacts).Quadratic contacts-possibly informing complex cognitive abilities-have been neglected in post-conflict studies.We investi-gated quadratic affliation in semi-free ranging pigs Sus scrofa,at the ethical farm Parva-Domus(Cavagnolo,Italy).Kinship was known.We collected behavioral data on adult pigs(n=104)via video recordings(43 h)followed by video analyses.Affiliative and anxiety behaviors between bystanders were collected under post-conflict(PC;following a conflict between non-bystanders)and matched-control(MC;no conflict)conditions.Quadratic affiliation was present in pigs,as bystanders affliated more in PC than MC,and such affiliation was followed by a decrease in the anxiety behaviors of both the interacting bystanders.Thus,quadratic contacts may be partly aimed at reducing one's own anxiety(intrinsic regulation).Quadratic affiliation was highest between closely related bystanders,which suggests that such affiliation may be most effective when close kin is involved.Quadratic affiliation was lowest after reconciliation and spontaneous triadic contacts.This suggests that direct peacemaking between opponents and spontaneous triadic contacts with close kin may most likely replace quadratic affiliation.Hence,pigs can be influenced by the negative events that affect other pigs-but not themselves-and their response may be modulated by social factors.Such non-random quadratic affiliation may point toward the presence of elements of social appraisal abilities inpigs.