Monkeys Really Do 'Talk To Each Other'

Life Style Extra
May. 18, 2006

Monkeys do indeed talk to each other just like humans - and scientists have started to unravel their primitive language.

It is the first time meaningful sounds have been identified in the animal kingdom after British researchers found putty-nosed monkeys share the uniquely human ability to string utterances together to convey messages.

The tree-dwelling creatures have two distinct calls to alert each other to danger.

So "pyow, pyow, hack, hack, hack" is translated from monkey speak to mean something like "c'mon - we're outta here."

During observations of the species in the Gashaka Gumti National Park, Nigeria, Doctors Kate Arnold and Klaus Zuberbuhler found the monkeys often produced strings of calls containing their two main call types.

The researchers also noticed a particular sequence of calls appeared to mean something else entirely when strung together.

The new string of calls consisted of the species' two basic call sounds - 'pyows' used to warn against a loitering leopard and 'hacks' used to indicate a hovering eagle.

These 'sentences', consisting of several pyows followed by a few hacks, appear to function as a command to the group to move away to safer terrain.

Dr Arnold said: "These calls were not produced randomly and a number of distinct patterns emerged.

"One of these patterns was what we have termed a 'pyow-hack sequence'. This sequence was either produced alone or inserted at certain positions in the call series.

"Observationally and experimentally we have demonstrated that this call sequence serves to elicit group movement in both predatory contexts and during normal day-to-day activities such as finding food sources and sleeping sites.

"The pyow-hack sequence means something like 'let's go' whereas the pyows by themselves have multiple functions and the hacks are generally used as alarm
calls."

The research was initially aimed at finding out whether male putty-nosed monkeys produce alarm calls which go beyond simply alerting other group members to danger but which also 'label' the predator type.

The researchers, whose findings are published in Nature, found putty-nosed monkeys do not demonstrate this capability - instead noticing a series of calls which appeared to combine different calls to express new meanings.

The more complex calls may represent an efficient way to use a restricted repertoire.

Rather than creating a new sound, the monkeys can encode fresh information by combining two existing ones.

Dr Arnold said: "Previously animal communication systems were considered to lack examples in which call combinations carried meanings that were different to the sum of the meanings of the constituent elements.

"This is the first good example of calls being combined in meaningful ways.

"The implications of this research are that primates, at least, may be able to ignore the usual relationship between an individual call and any meaning that it might convey under certain circumstances."

Dr Arnold said the groups are more likely to move away to escape a prowling leopard but stay still and out of sight if an eagle is overheard.

Crucially males also issued the phrase when no predators threatened to prompt foraging in the mornings and find somewhere to sleep in the late evenings.

She said: "We heard it whenever the male wanted the group to move."

Dr Zuberbuhler said: "To our knowledge, this is the first good evidence of a syntax-like natural communication system in a non-human species."