Monkeys far smarter than thought

New York: Researchers have uncovered a sophisticated primate language of monkeys which even has local dialects and found that they can form basic 'sentences' to communicate. The same species of monkeys located in separate regions use their alarm calls differently to warn of approaching predators, a linguistic analysis by a team of scientists has revealed.

The combined team of linguists and primatologists analysed alarm calls of Campbell's monkeys on two sites - the Tai forest in Ivory Coast and Tiwai Island in Sierra Leone. "Our findings show that Campbell's monkeys have a distinction between roots and suffixes, and that their combination allows the monkeys to describe both the nature of a threat and its degree of danger," said Philippe Schlenker, the lead author and professor at New York University.

Whereas the primates were threatened by eagles on Tiwai Island, eagles and leopards threatened them in the Tai Forest. Using transcriptions of these monkey calls, gathered in field experiments involving playbacks of predator calls, the researchers found greater complexity in expression than previously understood.

These calls make a distinction between roots (especially 'hok' and 'krak') and suffixes (-oo). Their combination allows the monkeys to describe both the nature of a threat and the degree of danger. Thus, 'hok' warns of serious aerial threats, usually eagles, whereas 'hok-oo' can be used for a variety of general aerial disturbances. The calls are not used in the same way in the Tai Forest and on Tiwai Island.

In the long term, the research should help initiate the development of a form of 'primate linguistics' -- the application of sophisticated methods from contemporary formal linguistics to systems of animal communication, Schlenker said. The study appeared in the journal Linguistics and Philosophy.