Not just females: the socio-ecology of social interactions between spider monkey males

Abstract

Male–male relationships are mostly characterized by competition. However, males also cooperate with one another if socio-ecological conditions are suitable. Due to their male philopatry, the need for cooperation in home range defence and high degree of fission–fusion dynamics, spider monkeys provide an opportunity to investigate how male–male interactions are associated with socio-ecological factors, such as the presence of potentially receptive females, the degree of food availability and the likelihood of home range defence. We tested predictions about changes in social interactions between wild spider monkey males in relation to these factors. First, males did not change their interaction patterns when potentially receptive females were in the subgroup compared to when they were absent. Second, males tended to be less tolerant of one another when feeding, but spent more time grooming, in contact and proximity with one another when food availability was lower than when it was higher. Third, males exchanged fewer embraces, spent less time grooming, in proximity and in contact with one another, and spent more time vigilant at the home range boundary area than at other locations. Our findings contribute to the understanding of social flexibility and the importance of considering males in socio-ecological models of any group-living species.

Rapid facial mimicry in Platyrrhini: Play face replication in spider monkeys (Ateles fusciceps, Ateles hybridus, and Ateles paniscus)

“…Our study did not reveal any evidence of RFM modulation based on either individual factors-such as sex, age, and species-or social factors, such as relationship quality and kinship. This lack of RFM modulation could be associated with the flexible nature of social relationships in spider monkeys, as indicated by previous studies (Aureli & Schaffner, 2008;Aureli et al, 2013;Saldaña-Sánchez et al, 2022). In spider monkeys, male-male relationships may not be consistently strong as generally described and can be marked by a dynamic interplay of cooperation and competition (Aureli et al, 2013;Saldaña-Sánchez et al, 2022).…”

“…This lack of RFM modulation could be associated with the flexible nature of social relationships in spider monkeys, as indicated by previous studies (Aureli & Schaffner, 2008;Aureli et al, 2013;Saldaña-Sánchez et al, 2022). In spider monkeys, male-male relationships may not be consistently strong as generally described and can be marked by a dynamic interplay of cooperation and competition (Aureli et al, 2013;Saldaña-Sánchez et al, 2022). On the other hand, females may exhibit a high level of affiliation under specific conditions, such as experiencing stress (Rodrigues, 2013) or facing ecological constraints (Abondano & Link, 2012).…”

“…Among females, relationships are typically weak and centered on infants. On the other hand, while males tend to form alliances and develop strong bonds compared to females, young males may face the risk of attacks by adult males when attempting to engage in social interaction with them, as young males can be perceived as potential competitors (Aureli & Schaffner, 2010;Saldaña-Sánchez et al, 2022).…”

“…Among females, relationships are typically weak and centered on infants. On the other hand, while males tend to form alliances and develop strong bonds compared to females, young males may face the risk of attacks by adult males when attempting to engage in social interaction with them, as young males can be perceived as potential competitors (Aureli & Schaffner, 2010; Saldaña‐Sánchez et al, 2022). Hence, during play (especially play fighting), individuals have to effectively communicate the nature of their actions by using clear and unambiguous signals such as the play face (Cordoni & Palagi, 2012; Palagi & Cordoni, 2012; Palagi et al, 2016).…”

Despite COVID: showcasing new research in evolutionary biology from academic care-givers in the middle of a pandemic

“…Traditionally the focus of male-male interactions has been on competition, but Saldaña-Sánchez et al [27] show that male spider monkeys' behaviour is influenced by some socio-ecological factors, such as food availability and proximity to the home range boundary, but not others, such as the presence of receptive females, suggesting ways that males in this male-philopatric, fission-fusion society can flexibly adjust their relationships to allow for both cooperation and competition. Lew-Levy et al [28] found that information transmission about spear hunting in BaYaka foragers occurred through costly teaching, typically direct instruction, which differs from other domains in which learning occurs through lower-cost mechanisms.…”