News Animals

Territorial conflict may explain male primates’ large size

The latent threat of rival groups may select for larger males, even without frequent fights

Two adult snub-nosed monkeys sit together, with a juvenile between them and a bare winter landscape in the background.

Some male primates are much larger than their female counterparts. For example, male black-and-white snub-nosed monkeys ( right) dwarf the females of the species (left).

Cyril Grueter

By Jake Buehler

It’s a game of monkey mean, monkey grew. Territorial tension may be behind the size of male primates.

In many primate species, males have evolved to be bigger than their female counterparts, a disparity typically attributed to competition among socially related males for access to females.