Dominance among male chimpanzees in the Mahale Mountains National Park, Tanzania: A preliminary study

Hayaki, Hitoshige; Huffman, Michael A.; Nishida, Toshisada

doi:10.1007/bf02381303

Cited by 49 publications

(44 citation statements)

References 9 publications

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“…To assess the dominance rank similarity of dyads, we recorded the direction of pant grunts, a formal signal of submission given by low ranking individuals to high ranking animals (40,41). We then used Version 1.0 of the MatMan software package (42) to assign dominance ranks to males in each of the 7 years of study.…”

Section: Methodsmentioning

confidence: 99%

The limited impact of kinship on cooperation in wild chimpanzees

Langergraber

Mitani

Vigilant

2007

Proc. Natl. Acad. Sci. U.S.A.

356

306

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The complex cooperative behavior exhibited by wild chimpanzees generates considerable theoretical and empirical interest, yet we know very little about the mechanisms responsible for its evolution. Here, we investigate the influence of kinship on the cooperative behavior of male chimpanzees living in an unusually large community at Ngogo in Kibale National Park, Uganda. Using long-term field observations and molecular genetic techniques to identify kin relations between individuals, we show that male chimpanzees clearly prefer to affiliate and cooperate with their maternal brothers in several behavioral contexts. Despite these results, additional analyses reveal that the impact of kinship is limited; paternal brothers do not selectively affiliate and cooperate, probably because they cannot be reliably recognized, and the majority of highly affiliative and cooperative dyads are actually unrelated or distantly related. These findings add to a growing body of research that indicates that animals cooperate with each other to obtain both direct and indirect fitness benefits and that complex cooperation can occur between kin and nonkin alike.Pan troglodytes ͉ genotyping ͉ kin recognition ͉ microsatellites ͉ relatedness

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Section: Methodsmentioning

confidence: 99%

The limited impact of kinship on cooperation in wild chimpanzees

Langergraber

Mitani

Vigilant

2007

Proc. Natl. Acad. Sci. U.S.A.

356

306

View full text Add to dashboard Cite

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“…Pant grunts are vocal signals of submission given by low-ranking chimpanzees to highranking chimpanzees (Bygott 1979;Hayaki et al 1989). We ordered individuals from top to bottom so as to minimize the number of reversals in the matrix.…”

Section: Study Site and Subjectsmentioning

confidence: 99%

Female parity, male aggression, and the Challenge Hypothesis in wild chimpanzees

2012

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The Challenge Hypothesis proposes that testosterone mediates aggression during periods of heightened conflict between males, especially episodes that have important fitness consequences. Considerable evidence from seasonally breeding species provides support for this hypothesis, but few data exist in animals that mate yearround. We tested predictions generated by the Challenge Hypothesis in chimpanzees, a non-seasonally breeding primate, through a study of individuals living in an exceptionally large community at Ngogo, Kibale National Park, Uganda. Results indicated that dominance rank had no influence on testosterone levels. Instead of rank influencing testosterone production, additional analyses revealed an important role for reproductive competition. Male chimpanzees displayed more aggression when they were in the same party as parous estrous females than when reproductively active females were unavailable. Male chimpanzees competed more intensely for mating opportunities with parous females than with nulliparas, and as a consequence, males displayed more aggression around the former than the latter. When males accompanied parous estrous females, their urinary testosterone concentrations were significantly higher than baseline concentrations. In contrast, urinary testosterone concentrations did not exceed baseline when males associated with nulliparous estrous females. These differences in testosterone levels could not be attributed to mating per se because males copulated equally often with parous and nulliparous females. Furthermore, variation in testosterone concentrations were not due to males gathering together in large parties, as their levels in these situations did not exceed baseline. Taken together, these findings, derived from a relatively large sample of males and estrous females, replicate those from a prior study and furnish additional support for the Challenge Hypothesis. Our results suggest that the Challenge Hypothesis is likely to be broadly applicable to chimpanzees and increase our understanding of the physiological costs to males who compete for estrous females.

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“…Within communities, male chimpanzees strive for status as they attempt to dominate others, forming linear dominance hierarchies in the process. 46,[51][52][53] Recent research from several sites now indicates that males achieving high dominance rank obtain substantial fitness benefits, with alpha males siring up to 30%-50% of all infants born during their tenures at the top of hierarchies. [53][54][55][56] Male chimpanzees also compete with conspecifics from other communities as they defend their feeding grounds via group territorial behavior.…”

Section: Male Chimpanzee Cooperationmentioning

confidence: 99%