Color vision drove primates to develop red skin and hair, study finds

May 24, 2007

You might call it a tale of "monkey see, monkey do." Researchers at Ohio University have found that after primates evolved the ability to see red, they began to develop red and orange skin and hair.

Humans, apes and Old World monkeys, such as macaques and leaf monkeys, all have trichromatic vision, which allows these primates to distinguish between blue, green and red colors. Primatologists have disagreed about whether this type of color vision initially evolved to help early primates forage for ripe fruit and young, red leaves among green foliage or evolved to help them select mates.

Now a new study published online this week in American Naturalist by Ohio University researchers Andre Fernandez and Molly Morris rules out an initial advantage for mating and suggests that red-color vision evolved for non-social purposes, possibly foraging. But once developed, trichromaticism drove the evolution of red skin and hair through sexual selection.

Fernandez, the study's lead author, first began to question the strict correlation of food choice and color vision while studying howler monkeys in Costa Rica. He recently compiled data on the color vision, social and sexual habits and red skin and pelage of 203 different primate species.

The researchers then used a phylogenetic tree representing the evolutionary relationships among all the primate species under study to test hypotheses about the order in which the traits of red color vision, gregariousness (highly social behavior) and red coloring evolved. By comparing the traits of individual species in this evolutionary context, Fernandez and Morris could statistically deduce the probability of their ancestors having the same traits, as well if any of the traits were correlated with one another.

They found that the species that could discern red and orange hues were more likely to develop red and orange skin and hair, as well as highly social habits that make it easier to visually compare mates. In fact, the more social the trichromats are, the more red coloring they show.

"Neuroscience research has found some evidence of a perceptual bias for more brilliant colors," said Fernandez, an Ohio University doctoral student. "So, it is reasonable for primates with trichromatic color vision to respond more when they see bright colors."

So while foraging may have initially sparked red color vision, the new ability was likely "recruited" for social purposes.

"It looks like red skin and hair became a sexual preference," said Morris, a fish biologist who studies how physical traits such as coloring evolve through sexual selection. "So while the benefits in terms of eating may not apply anymore, the (red-color) vision in some groups is now relevant in social terms."

Source: Ohio University

Explore further: Transparent larvae hide opaque eyes behind reflections

add to favorites email to friend print save as pdf

Related Stories

Facebook dressed down over 'real names' policy

29 minutes ago

Facebook says it temporarily restored hundreds of deleted profiles of self-described drag queens and others, but declined to change a policy requiring account holders to use their real names rather than drag names such as ...

Far more displaced by disasters than conflict

49 minutes ago

Disasters last year displaced three times more people than violent conflicts, showing the urgent need to improve resilience for vulnerable people when fighting climate change, according to a study issued ...

Apple iOS 8 software bug affects health apps

1 hour ago

A bug in Apple's new iOS 8 software for mobile devices is prompting the company to withhold apps that use a highly touted feature for keeping track of fitness and health data.

Recommended for you

Stem cells use 'first aid kits' to repair damage

2 hours ago

Stem cells hold great promise as a means of repairing cells in conditions such as multiple sclerosis, stroke or injuries of the spinal cord because they have the ability to develop into almost any cell type. ...

User comments : 0