Regardless of one's feelings regarding zoos, it doesn't take much time spent in the primate house to come away with a feeling of kinship to our closest living relatives. Although not human, we recognize in chimpanzees and bonobos some of the same traits we display.
It's not an observation that escapes biologists, either. Researchers are often interested in the common behaviors and traits we share with other higher primates to give us clues as to the evolutionary origins of human intelligence. A new study published this week in PNAS from scientists at the Yerkes National Primate Research Center has looked at the use of hand gestures by chimpanzees and bonobos as a form of communication. The idea behind this study is to gain a better understanding of the roots of human language development.
Although both species of primate use vocalizations and facial expressions to communicate, they also use hand gestures. Unlike the vocalizations and facial expressions, however, hand gestures don't mean the same things to both chimpanzees and bonobos. They stem from, and are interpreted by, different parts of the brain.
The study involved looking at the different facial/vocal and manual displays from two groups of bonobos and two groups of chimpanzees. The researchers identified 31 different manual gestures, and 18 facial/vocal displays that related to a range of different behavioral activities such as grooming, feeding, playing, and so on. It turns out that the facial/vocal displays could be recognized regardless of whether the viewer belonged to the same group or even species.
