Sexual dimorphism in chimpanzee (Pan troglodytes schweinfurthii) and human age-specific fertility

Muller, Martin N.; Jones, Nicholas; Colchero, Fernando; Thompson, Melissa Emery; Enigk, Drew K.; Feldblum, Joseph T.; Hahn, Beatrice H.; Langergraber, Kevin E.; Scully, Erik J.; Vigilant, Linda; Walker, Kara K.; Wrangham, Richard W.; Wroblewski, Emily E.; Pusey, Anne E.

doi:10.1016/j.jhevol.2020.102795

Cited by 24 publications

(30 citation statements)

References 93 publications

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“…The results presented here suggest that adolescent male chimpanzees, who cannot effectively compete with older males nor sexually coerce adult females, employ at least two behavioural tactics to mate and reproduce. First, as reported in previous research, adolescent males appear to target adolescent, nulliparous females as mating partners; they mate with nulliparous females frequently and father their first offspring more often in adolescence than they do in adulthood [42,48]. Our findings also corroborate past research indicating that nulliparous female chimpanzees are less preferred as mating partners than are parous females.…”

Section: Discussionsupporting

confidence: 90%

“…Specifically, as male chimpanzees transition from adolescence to adulthood and rise in dominance rank, they show less sexual interest in nulliparous females and target them for aggression infrequently [47]. High-ranking males also rarely father the first offspring of these females [33][34][35][36][37]42]. Second, mating success for adolescent and young adult males was predicted by the strength of affiliative bonds that males formed with females.…”

Section: Discussionmentioning

confidence: 99%

“…To do so, we conducted two mixed effects logistic regression analyses where the outcome variable was whether a male was the father of an infant he had the opportunity to sire. We considered males who were at least 9 years old at the time of the infant's conception as potential fathers because this is the age of the youngest known sire in chimpanzees [41,42]. We also excluded males as potential sires of infants born to their mothers or maternal sisters, as this type of close inbreeding has not been documented at Ngogo and occurs rarely in chimpanzees elsewhere [63].…”

Section: (Ii) Paternity Successmentioning

confidence: 99%

“…In this context, nulliparous, adolescent female chimpanzees cycle for many years without conceiving and often lose their first offspring [43][44][45][46]. Adult males typically show little sexual interest in these females [42,47]. Adolescent male chimpanzees consequently target nulliparous females as mating partners and primarily reproduce with these first-time mothers [42,48].…”

Section: Introductionmentioning

confidence: 99%

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The development of affiliative and coercive reproductive tactics in male chimpanzees

et al. 2021

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Like many animals, adult male chimpanzees often compete for a limited number of mates. They fight other males as they strive for status that confers reproductive benefits and use aggression to coerce females to mate with them. Nevertheless, small-bodied, socially immature adolescent male chimpanzees, who cannot compete with older males for status nor intimidate females, father offspring. We investigated how they do so through a study of adolescent and young adult males at Ngogo in Kibale National Park, Uganda. Adolescent males mated with nulliparous females and reproduced primarily with these first-time mothers, who are not preferred as mating partners by older males. Two other factors, affiliation and aggression, also influenced mating success. Specifically, the strength of affiliative bonds that males formed with females and the amount of aggression males directed toward females predicted male mating success. The effect of male aggression toward females on mating success increased as males aged, especially when they directed it toward females with whom they shared affiliative bonds. These results mirror sexual coercion in humans, which occurs most often between males and females involved in close, affiliative relationships.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: (Ii) Paternity Successmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The development of affiliative and coercive reproductive tactics in male chimpanzees

et al. 2021

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“…For inference on age-specific fecundity, we used the Bayesian inference model proposed in Muller et al (2020). This approach uses a Poisson or binomial mixed regression with individual random effects.…”

Section: Inference On Age-specific Survival and Fecunditymentioning

confidence: 99%

Evidence of demographic buffering in an endangered great ape: Social buffering on immature survival and the role of refined sex‐age classes on population growth rate

Colchero

Eckardt

Stoinski

2021

Journal of Animal Ecology

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1. Theoretical and empirical research has shown that increased variability in demographic rates often results in a decline in the population growth rate. In order to reduce the adverse effects of increased variability, life-history theory predicts that demographic rates that contribute disproportionately to population growth should be buffered against environmental variation. To date, evidence of demographic buffering is still equivocal and limited to analyses on a reduced number of age classes (e.g. juveniles and adults), and on single sex models.

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Behavioral Ecology

and¹,

Hawkes²

2023

A Companion to Biological Anthropology

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Sexual dimorphism in chimpanzee (Pan troglodytes schweinfurthii) and human age-specific fertility

Cited by 24 publications

References 93 publications

The development of affiliative and coercive reproductive tactics in male chimpanzees

The development of affiliative and coercive reproductive tactics in male chimpanzees

Evidence of demographic buffering in an endangered great ape: Social buffering on immature survival and the role of refined sex‐age classes on population growth rate

Behavioral Ecology

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