Jealous of mom? Interactions between infants and adult males during the mating season in wild squirrel monkeys (<i>Saimiri collinsi</i>)

Abstract

&#x0D; &#x0D; &#x0D; Squirrel monkeys (Saimiri collinsi) are seasonal breeders that live in large social groups in which females are dominant to males. Females have one infant per year, and the nursing period lasts six to eight months. Preliminary observations in the wild indicated that during the mating period (eight weeks: July and August in our population), the infants show agonism directed at males who approach their mothers. This directed sexual interference by infants has rarely been reported for neotropical primates. Our study reports observations in a natural population of Saimiri collinsi with the aim of describing the social behavior of infants during the breeding season, especially with regard to adult males in the group. Infants of both sexes were observed during three mating periods (2011, 2012, 2013), to test hypotheses about the possible function of infant harassment directed at adult males. The behavior of infants (variables: activity and nearest neighbor) was sampled by the focal animal method as well as ad libitum observations. We recorded 99 cases of agonism and 17 cases of tolerance between nearby males and infants via the all-occurrence method. Thus, 85% of interactions between adult males and infants involved agonism. These results suggest that infant interference can present a cost to adult males during the breeding season.&#x0D; &#x0D; &#x0D;

Sexual Interference Behaviors in Male Adult and Subadult Tibetan Macaques (Macaca thibetana)

“…Sexual interference is any form of disruptive behavior in which group member(s) influence or attempt to influence a dyad’s ongoing copulatory behaviors [ 3 , 4 , 5 , 6 , 7 , 8 ]. In nonhuman primates, sexual interference has been studied in several species, including stump-tail macaques ( Macaca arctoides ), chimpanzees ( Pan troglodytes ), golden snub-nosed monkeys ( Rhinopithecus roxellana ), and squirrel monkeys ( Saimiri collinsi ) [ 9 , 10 , 11 , 12 ]. Examples of interference behaviors include group members approaching mating males and females and vocalizing, reaching toward, and slapping at the mating male and/or female, moving around the pair, and sometimes making physical contact with them [ 9 , 13 , 14 , 15 ].…”