Intrasexual competition and sexual selection in cooperative mammals

It tends to be the sex that invests least in its offspring that develops the more pronounced secondary sexual characteristic and competes more intensely for access to the opposite sex. A twelve-year study of meerkats throws light on an animal that is an exception to this rule. Although female meerkats invest more heavily in their progeny than males, they compete more strongly for reproductive opportunities; traits affecting competitive success have a stronger influence on their reproductive success; and they show greater development of secondary sexual characters associated with reproductive competition. This unusual behaviour may stem from the fact that resources necessary for the females' successful reproduction are heavily concentrated and potentially scarce, so that the emphasis on intrasexual competition for breeding opportunities becomes as strong or stronger in females as in males.