Guenon monkeys’ colourful and varied faces have evolved as a way to avoid crossbreeding, scientists have found.
Many different species of guenons live side-by-side meaning mating with other species, which could lead to infertile offspring, is a possibility.
The researchers used human facial recognition technology to identify primate features from photographs.
They found that guenons’ looks have evolved to become more distinctive from their relatives living close by.
The findings are reported in the journal Nature Communications and researchers say they are the best evidence to date of visual signs acting as a barrier to breeding across species.
Guenons - Cercopithecini - are a group of more than 25 species of monkeys which originated in the forests of Central and West Africa.