Female gorillas must balance the reproductive costs of staying with or leaving an older male

Date: September 11, 2019

Source: Max Planck Institute for Evolutionary Anthropology

When a gorilla group's silverback is close to the end of his reproductive years, females face a dilemma: Should they stay with him until he dies or leave him for another male? A team of researchers has now found that both strategies bear its costs: females face reproductive costs of staying with an older male as well as costs when they transfer to a new silverback.

In western lowland gorillas, groups consist of several females and only one adult male, the silverback. With his impressive body size, he protects his group against predators and other adult males. Females rely on this protection and never travel alone, however they may change groups multiple times during their lives. "Female gorillas seem to have different strategies when it comes to reproduction and transfer," says Marie Manguette, first author of the study. "We have observed females transferring to another group after every weaned offspring and therefore up to six times in their lives, while others have stayed and bred with the same male for 20 years."

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