While other primates have exhibited simple vocabularies, it has long been believed that syntax, the construction of sentences, was unique to humans. But a recent study suggests that at least one species of monkey communicates in vocalized sentences.
A research team led by Klaus Zuberbühler of the University of St. Andrews has been studying the calls of the Campbell’s monkey, a primate found in the Ivory Coast. The team looked at how the calls of adult male monkeys vary in response to various stimuli. Campbell’s monkeys have six different types of individual calls, each of which has a distinct meaning. What’s surprising, however, is that these monkeys actually string together multiple types of calls to create communications with entirely new meanings. Zuberbühler and his team claim this is a form of syntax, suggesting that Campbell’s monkeys have developed a sort of sentence structure. Other primates, such as chimpanzees, have shown an understanding of language, able to connect words and symbols with specific meanings, but haven’t been able to combine those words into sentences.
The team has identified the meanings of the individual calls, as well as how they can be combined to form completely different communications:
The “boom-boom” call invites other monkeys to come toward the male making the sound. Two booms can be combined with a series of “krak-oos,” with a meaning entirely different to that of either of its components. “Boom boom krak-oo krak-oo krak-oo” is the monkey’s version of “Timber!” – it warns of falling trees.
Combining the “boom-booms” and “krak-oos” with a third sound, “hok-oo,” warns monkeys of the presence of other monkey groups. It appears that initially, the monkeys developed the calls to warn each other of specific predators, such as leopards and eagles, but their anti-predator vocabulary has evolved into something much more sophisticated.
Boom! Hok! A Monkey Language Is Deciphered [NY Times]
