MPIDR Working Paper
To care or to fight: must primate males choose?
MPIDR Working Paper WP-2010-032, 26 pages.
Rostock, Max Planck Institute for Demographic Research (October 2010)
Females in all mammalian species care for their offspring, while most mammalian males do not. This failure of paternal investment is generally explained in terms of a trade-off between paternal care and mating competition. While there has been great interest in the optimal pattern of investment in paternal care versus mating effort, comparative evidence that such a trade-off exists has not been published for any large group of mammal species. We employ comparative data on primates to test for such a trade-off. Across primate species, the degree to which males engage in direct care of young is inversely related to levels of overt male-male conflict, and to canine dimorphism, a morphological measure associated with male-male conflict. When phylogeny is taken into account, there is no significant relationship between sex-biased longevity and whether males engage in care, implying that investment in care and investment in competition are functional alternatives to each other. Males of most primate species engage in either intensive direct care, or intense or frequent intrasexual competition, but not both. The hypothesis that investment in care and in intrasexual conflict are alternative strategies is strongly supported.