Southeastern Asian forests harbor a small-bodied line of apes, known as gibbons, that sing like rainforest Pavarottis. These animals' full-throated refrains reverberate through dense vegetation.
A research team has now gone behind the music and gleaned the first evidence that singing gibbons rearrange notes to communicate with their comrades. This simple system, or syntax, for recombining sounds to convey messages represents a step toward human language that had not previously been demonstrated in apes, says psychologist Esther Clarke of the University of St. Andrews in Scotland.
Researchers have traditionally held that syntax arose only as the vocabulary of prehistoric people grew large and unwieldy. "We're finding the