Guenon monkeys have some of the most colorful, distinctive faces in the primate world. These animals could use their stylistic looks to help avoid interbreeding, based on new research.
There are up to 35 species of the genus, which live in forested regions of west and central Africa. They are also known as cheek pouch monkeys. Guenon monkeys range in size between that of a large cat to a small dog.
The monkeys often forage for food in groups containing individuals of more than one species. Each variety of Guenon monkey uses a unique set of chirps, sneezes and whistles to communicate. However, like many people in the dense linguistic map of Europe, the primates learn many of the "words" of "foreign" languages. Researchers believe this ability leads to a higher survival rate for all the creatures.
William Allen, of the University of Hull in the United Kingdom, led a study that examined more than 20 species of the monkeys.
They found the animals rarely mated between species, preferring their own species. In captivity, different varieties of the monkey have been observed breeding. Allen believes the animals may avoid breeding with other species as a means of avoiding sterile or weakened offspring.
Facial recognition software was used to study the same ability in Guenon monkeys. Photographs of 150 primates were provided as input to the application. Pictures came from both captive and wild monkeys. The team then examined how facial characteristics differed within individual species.
They found little difference within species, with each individual looking nearly-identical to other members of the group. However, there are vast differences between one species of Guenon monkey and another. Fur coloration, noses, lips and many other features easily identify the species in a given individual.
Facial distinctiveness between species, while maintaining similarities within varieties, could assist the species as it travels throughout the environment. Groups long-separated by time and distance would recognize each other when they meet once more, researchers believe. Re-combination of primate populations can occur with the loss of habitat from natural or man-made causes.
"Evolution produces adaptations that help animals thrive in a particular environment, and over time these adaptations lead to the evolution of new species," James Higham, assistant professor of Anthropology at New York University, said.
In an independent study, investigators examining monkeys in South America believe they have also recognized similar behavior among primates on that continent.
Markings on some wild animals are used in communication, signifying individuality. Biologists theorized this might be the case with Guenon monkeys, but research did not find any evidence to support this theory.
Investigation of facial characteristics in Guenon monkeys was profiled in the journal Nature Communications.
