Effects of age and sex on intra-group spacing behaviour in juvenile savannah baboons, Papio cynocephalus cynocephalus

Abstract

Twenty juvenile members of known genealogies in two baboon groups were studied over a 16month period to evaluate a number of predictions about juvenile spacing behaviour based on the natural history of savannah baboons. Young juveniles (1-2.5 years old) approached more frequently and spent more time in proximity to other group members than did old juveniles (3-5.5 years old). In particular, young juveniles associated more closely with their mothers, particular adult males (possible fathers) and age-peers than did old juveniles. Approaches of young juveniles towards unrelated, high-ranking adults were more likely to occur during feeding than were those of old juveniles. Also, following such an approach, young juveniles were more likely than old juveniles to begin feeding immediately. The overall rates of feeding of old juveniles were depressed when they were in proximity to unrelated, high-ranking adults, whereas the feeding rates of young juveniles were not. Juvenile males approached adult males more often than did juvenile females. Juvenile females approached unrelated adult females more often than did juvenile males. Sex differences also existed in juveniles' choices of unrelated adult female neighbours. Juvenile females associated most often with lactating females, whereas juvenile males associated primarily with cycling females. During group resting, juvenile females approached adult females from higherranking matrilines more often than they approached adult females from lower-ranking matrilines. Juvenile males did not exhibit this attraction. Also, among old juveniles, females associated closely with their mothers, whereas males did not. Taken together, the results support the hypotheses that juvenile baboons associate with group members in ways that (1) enhance the probability of surviving an early period of high mortality, (2) create opportunities for social learning of sex-typical behaviours/skills, and, for females, (3) facilitate acquisition of familial dominance status.

Cues to kinship and close relatedness during infancy in white-faced capuchin monkeys, Cebus capucinus

“…Natal male kin are therefore more concentrating into younger juvenile and sub-adult categories, while female kin remain distributed across a wider range of ages. Age proximity, and particularly peer group membership, is an important regulator of social interactions in capuchins (Schoof & Jack, 2014) and various other animals: gazelles (Walther, 1972), impalas (Murray, 1981), savannah baboons (Pereira, 1988;Alberts, 1999;Silk et al, 2006Silk et al, , 2010, rhesus macaques (Janus, 1992;Widdig et al, 2001Widdig et al, , 2002, chimpanzees (Mitani, 2009), humpback whales (Ramp et al, 2010), and giraffes: (Bercovitch & Berry, 2013). In species featuring high male reproductive skew during brief tenures, such as rhesus macaques, strong associations with peers can allow for different treatment of paternal half siblings as compared to more distant kin (Altmann, 1979;Widdig, 2007Widdig, , 2013.…”

Paternal effects on offspring fitness in a multimale primate society

“…Second, fathers may help offspring attain a higher quality and/or quantity of food; in Rhesus macaques, juveniles with persistent relationships with adult males (whose paternal status was unknown) gained greater access to food resources (37). This form of paternal care may be beneficial if offspring forage near their fathers and are thereby protected from feeding interruptions or if proximity to fathers helps them gain access to better food sources through observational learning of food types or foraging skills (38)(39)(40). Food acquisition influences both growth rates and age at maturity in a number of primate species (41,42), including baboons (35,43), and could be a major mediator of the paternal effects documented here.…”

Female rhesus macaques discriminate unfamiliar paternal sisters in playback experiments: support for acoustic phenotype matching

“…However, owing to the high skew in male reproduction found in many species [5,25], paternal siblings tend to be born in the same age cohort [26]. As age mates go through the same life-history stages at the same time, they can be found to preferentially interact with each other [27,28]. Age proximity was therefore suggested (at least) as a primary mechanism for paternal kin recognition [17,18].…”