Scientists decipher a monkey’s commands
Nigerian monkeys combine sounds to tell group it’s time to move on
[Reuters 2006-05-17]

[Photo] Kate Arnold. The male putty-nosed monkey, shown here in the wild, combines "pyow" and "hack" sounds to tell others in his group to move out.


LONDON - It could be mistaken for meaningless jabbering or sound effects from an action comic strip, but the "pyow hack hack pyow hack hack" noises of some African monkeys are a signal it is time to leave.

All animals make distinct sounds, but male tree-dwelling, putty-nosed monkeys in Nigeria can combine two noises in novel ways to convey new meaning ??? a trait that once was thought to be uniquely human.

"We found these monkeys make two different alarm calls, but in addition they combine the calls to convey to other group members that the troop should move on," said Klaus Zuberbuhler, a psychologist at the University of St. Andrews in Scotland.

Dominant putty-nosed male monkeys release the "pyow" sound when leopards are around, and the "hack" to warn of approaching eagles.

Zuberbuhler's colleague Kate Arnold discovered the monkeys' vocal talent while studying and recording how they reacted to sounds of leopards and eagles.

After replaying the tapes, the researchers noticed the call sequences the monkeys produced.

"Whenever they do the sequence, the troop moves on and leaves. By combining these two alarm calls into a high-order sequence, they generate a third meaning that tells everyone it is a good idea to move on," said Zuberbuhler, who reported the findings in Thursday's issue of the journal Nature.

He added that songbirds are known to combine sounds in structure sequences, but it has not been linked to meaning or a command to others.