Monkeys and apes have an evolutionary “Facebook”

By Casey Frye, CCNN Writer

monkey faces
Can you guess which primates are more social? I’ll give you a hint – they’ll have more colors.

Did you ever notice that some monkeys and apes have very colorful faces? Biologists from the University of California, Los Angeles (UCLA) reported that primates from Central and South America have spent 25 million years diversifying – becoming more different from one another. According to the UCLA researchers, this helps them participate in nature’s version of Facebook!

The researchers found that monkeys who are more social and hang out in large groups have more complex facial patterns, which helps them tell one monkey from another. “Humans are crazy for Facebook, but our research suggests that primates have been relying on the face to tell friends from competitors for the last 50 million years and that social pressures have guided the evolution of the enormous diversity of faces we see across the group today,” said Michael Alfaro, a UCLA professor and senior author of the study.

Alternatively, monkeys who hang out in smaller groups have simpler face patterns with less colors. Researchers believe this is because color is very important for identifying species, while also distinguishing individual primates within a species. “Faces are really important to how monkeys and apes can tell one another apart,” said Alfaro. With a smaller group, there’s less of a need for facial differences.

Location may have also played a role for the different colors. The researchers found that primates closer to the equator had darker colored skin, while those further away from it had lighter complexions. So, if a monkey is light and has complex facial colors, chances are they are social and live far from the equator. On the other hand, dark monkeys with complex facial patterns and darker skin are also social, but live closer to the equator. As Alfaro explains it, “Darkness or lightness is explained by geography and habitat type. Facial complexity is better explained by the size of your social group.”

Images courtesy of UCLA.