20.04.2014 - 22:58
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Behavioural and endocrinological correlates of male mate competition and reproduction in bonobos

by Martin Surbeck

TMartinhe bonobo society is characterized by high dominance status of adult females, co-dominance between the sexes, and cooperation and alliance formation between females. This is perhaps one of the reasons why previous research on bonobo has been biased towards social behaviour of females and the lack of information on males. However, in the light of the prominent function of female sexuality, is reasonable to assume that mating behaviour of males shows adaptations that enhance both mating success and reproductive success. Male bonobos have the reputation of being unusually peaceful and although agonistic encounters may be as frequent as in other primate species, the intensity of aggression appears to be low. Male aggression is usually related to the intensity of mate competition. When access to females can be monopolized, male contest is likely to lead to reproductive skew which can drive selection towards fighting ability and aggressiveness. This changes when males can not monopolise access to mates and under such circumstances, the need to invest in contest power and aggression will be reduced.

BonoboThis project investigates mechanisms of male mate competition and its implications for the social relations among males and between the sexes. The aim of this study is to elucidate the role of male bonobos in the context of mate competition, mating, and reproduction. Behavioural observations and corresponding endocrinological data are used to investigate mate competition and alternative mating strategies in relation to social parameters such as age, dominance status, and kinship.


Specifically the research focuses on:

  1. elucidating basic patterns of male social relations including male dominance relations, patterns of spatial associations and affiliative behaviour,
  2. investigating social parameters affecting male mating success and,
  3. relating male behaviour to changes in the steroid hormones testosterone and cortisol in order to understand mechanisms of male mate competition and costs associated with dominance ranks and mating strategies.