Monkey syntax?

` When the dominant male of a group of putty-nosed monkeys (Cercopithecus nictitans) sees a leopard, he makes the "pyow" call. When he sees an eagle, he makes the "hack" call. And when he wants to command the females and young to move on, he says pyow-pyow-pyow... hack hack hack hack!
` This is something only humans were thought capable of. Happily, this idea is now apparently proven wrong.
` Says the discoverer of this phenomenon, Kate Arnold of St. Andrews University;

“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.”

` Her colleague, Klaus Zuberbühler, said;

"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."

...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.

` Isn't that interesting? These monkeys are able to ignore the meaning of each individual 'pyow' and 'hack' when they are made together in a string, and instead interpret them to mean something else! In other words, the 'let's go' call is more than the sum of its pyows!
` I wonder how that could have come about, anyway? Perhaps some brilliant monkey decided to try using a sequence of 'alarm' calls to stir the others into motion, and after a while it caught on?

` Source: TimesOnline and Nature.