Colorful Primates Don't Have Better Color Vision, Study Finds
Published:10 Nov.2023    Source:University of Bristol

The findings, published this week in the Biological Journal of the Linnean Society, suggest that red skin and/or red-orange fur may be beneficial for use in social communication even in primate species that don't have particularly good colour vision. It's long been assumed that primates' colourful skin and fur is linked to their enhanced colour vision, and the results may have implications for understanding why these traits exist in different species.

Primates are known to use their red colour traits for communication with other members of their species, for example in signalling information about fertility or rank in the social hierarchy. It seems intuitive that having a better colour visual system that allows these traits to stand out more might have facilitated the evolution of these traits in the first place -- it would make sense for a species with better colour vision to evolve to be more colourful to take advantage of this ability.
Using photographs, the researchers categorised each species of primate in terms of having or not having particular colourful traits (e.g. red skin on the genital region or face, red-orange fur on different parts of the body). They then compared this colour information with each species' colour visual ability, taking into account the primate family tree, as well as a few other factors which might also influence coloration or colour visual ability such as whether they're nocturnal or diurnal and the size of the social group they live in. The aim was to find out whether species that have better colour vision are more likely to have red colouration, after controlling for other potential influencing factors.