Talking with the animals

16 Nov 2009

The discovery that apes can "talk" using hand gestures may shed more light on language development.

But these are not the only animals with communication skills - in the animal kingdom, it is all about getting your message out there.

And in a bid to understand how one of the most complex communication systems of all - human language - came about, scientists are also studying animals that, like us, use sound to communicate.

Surprisingly, they have discovered our closest relatives, despite their signing prowess, do not have much of a vocal repertoire.

Dr Klaus Zuberbuhler, an expert in primate communication from the University of St Andrews, UK, says: "Most of the non-human primate species only have a fairly limited number of sounds that they can generate."

Combining sounds

But while primate "vocabulary" is restricted, scientists have found many species can attach meanings to some sounds to convey information. Vervet monkeys, for example, have three distinct alarm calls that trigger three distinct response calls.

Some species, says Dr Zuberbuhler, can do even more: they possess the ability to use and understand simple grammar. Putty-nosed monkeys, he explains, can combine their calls to create a sequence that carries a more complex meaning.

In the laboratory, some primates have also demonstrated an understanding of human language; Kanzi, a male bonobo, is said to be able to understand about 3,000 words, as well as simple sentences.

His trainer Dr Sue Savage-Rumbaugh has said he can even combine words to form simple sentences of his own.

Kanzi is obviously intelligent, Dr Zuberbuhler comments, "but [he] is tested on human linguistic systems, not on his own natural way of communicating, and this is an artificial system".