Life history in male mandrills (Mandrillus sphinx): Physical development, dominance rank, and group association

Abstract

We assess life history from birth to death in male mandrills (Mandrillus sphinx) living in a semifree-ranging colony in Gabon, using data collected for 82 males that attained at least the age of puberty, including 33 that reached adulthood and 25 that died, yielding data for their entire lifespan. We describe patterns of mortality and injuries, dominance rank, group association, growth and stature, and secondary sexual character expression across the male lifespan. We examine relationships among these variables and investigate potential influences on male life history, including differences in the social environment (maternal rank and group demography) and early development, with the aim of identifying characteristics of successful males. Sons of higher-ranking females were more likely to survive to adulthood than sons of low-ranking females. Adolescent males varied consistently in the rate at which they developed, and this variation was related to a male's own dominance rank. Males with fewer peers and sons of higher-ranking and heavier mothers also matured faster. However, maternal variables were not significantly related to dominance rank during adolescence, the age at which males attained adult dominance rank, or whether a male became alpha male. Among adult males, behavior and morphological development were related to a male's own dominance rank, and sons of high-ranking females were larger than sons of low-ranking females. Alpha males were always the most social, and the most brightly colored males, but were not necessarily the largest males present. Finally, alpha male tenure was related to group demography, with larger numbers of rival adult males and maturing adolescent males reducing the time a male spent as alpha male. Tenure did not appear to be related to characteristics of the alpha male himself.

Bringing Up Baby: Developmental Simulation of the Adult Cranial Morphology of Rungwecebus Kipunji

“…Simulations based upon the Chlorocebus, Papio, and Mandrillus vectors fall away from the core group in the directions of their respective model taxa. Only the latter is substantially removed from the kipunji cluster, perhaps reflecting the extended development of male mandrills (Setchell et al, 2001;Setchell and Wickings, 2004;Setchell et al, 2006). On PC1, the M. sphinx simulation falls outside the core papionin group in the direction of mandrills and drills.…”

Coalitions in theory and reality: a review of pertinent variables and processes

“…For group-living animals, an individual RHP may be partially reflected in his place in a rank order based on dyadic dominance relationships (Noë, 1989). Indeed, several studies have shown that ordinal ranks (de Vries, 1998;de Vries & Appleby, 2000) and cardinal ranks (Boyd & Silk, 1983;Adams, 2005;Romero & Castellanos, 2010) correlate with some RHP components, such as body mass, body size, or age (e.g., Dittus, 1977;Packer, 1979;Jones, 1980;Clutton-Brock et al, 1982;Zucker & Clarke, 1998;Alberts et al, 2003;Setchell et al, 2006;Bissonnette et al, 2009b), but this is far from universal. For example, Fedigan (1992) reported that in wild capuchin monkeys, small, young and even incapacitated males have occupied alpha male positions, suggesting that social variables, instead of physical attributes of age and size, determine the dominance rankings of the males.…”

Color in competition contexts in non-human animals

“…However, colour is not closely related to overall body size, or weaponry in adult males, as alpha males are not always the heaviest or largest males, and do not necessarily have the longest canine teeth among the males in a group (Setchell, Wickings, & Knapp, 2006b). This suggests that relative testosterone levels are more important in male-male interactions than are small differences in size, perhaps because all males are well-armed, with long canine teeth, making motivation to fight more important than body size in male encounters.…”

“…Mandrills have long canine teeth, and escalated fights can occasion substantial costs to both combatants, including serious injury and death (Setchell et al, 2006b). Observational data suggest that male mandrills attend to colour in rivals: unidirectional submission occurs in male dyads with clear differences in red, but threats, contact aggression and unresolved 'standoff' encounters are more common where males are similar in colour, and thus unable to determine outcome of the encounter based on simple rules, suggesting that red coloration acts as a badge of status in male mandrills .…”