for National Geographic News
Putty-nosed monkeys put two different alarm calls together to create urgent warnings, according to observations recently made of the West African primates.
These monkey "sentences" appear to be evidence of what is widely considered to be a uniquely human ability: stringing words together to convey a message, or syntax.
"These monkeys combine different calls into more complex call sequences with novel meanings," said Klaus Zuberbühler, a psychology researcher at the University of St. Andrews in Scotland.
Zuberbühler co-wrote a study about the monkey calls appearing in tomorrow's issue of the journal Nature.
He and co-author Kate Arnold do not make a direct analogy between the monkeys' call sequences and human language. (Read related news: "Monkeys Deaf to Complex Communication, Study Says" .)
But Zuberbühler said that their work shows that "the main carriers of meaning are not the individual calls, but the call sequence."
Putty-nosed monkeys belong to a group of African monkeys called guenons. The species' most obvious distinguishing feature, and the one the animals are named for, is a bright white nose that stands out against a brown face.
The monkeys are found throughout the Ivory Coast (map of the Côte D'Ivoire), in parts of Liberia, and along the entire northwest coast of the Congo River.
Groups consisting of a single male accompanying 12 to 30 females and their offspring defend territories within this range.
Like other guenons, putty-nosed monkeys use two loud calls, usually referred to as "pyows" and "hacks." They use a series of pyows to warn of a leopard threatening the group and a string of hacks to indicate the presence of crowned eagles.
Zuberbühler and Arnold found that male monkeys often combine the two calls into a kind of simple sentence that they call a "pyow-hack."
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