Colorful monkeys called guenons sport moustaches, nose spots and ear tufts that make it easy to distinguish between different species of guenons. But to the average passers-by, monkeys of the same species might look strikingly similar.
In a new study, researchers uploaded 541 photographs of 110 monkeys of 12 different guenon species. The scientists found that a computer algorithm could correctly identify these monkeys by their faces, as well as distinguish among species. Scientists might be able to use algorithms like this one to study which factors are important in evolution, the researchers said. For instance, the algorithms could look at which aspects of a monkey's face are important to its evolutionary success.
The researchers also found that the algorithm they used in the study could not determine the monkeys' ages or sex from their faces, which suggests that guenon faces have not evolved to convey this information.
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"If communicating sex was a key aim of guenon faces, males and females should look different from their facial appearance, but for most species they don't," said James Higham, an assistant professor of anthropology at New York University and one of authors of the study.
Facial differences may provide vital clues to determining identity for guenon monkeys when they mate, the researchers said.