To test the primates response to danger, the team conducted a series of experiments in which they put models of predators — snow leopards, pythons and crested serpent eagles — near a group of gibbons and then made audio recordings of their response.
What they found, Clarke said, is that the gibbons approached the potential predator and began warbling a series of sounds — “wahs, wows and hoos” — that were picked up by other gibbons, who then repeated the calls to others.
The sounds made when encountering a predator were more chaotic and louder than those used to win over a mate, Clarke said. “Gibbons can rearrange their songs to denote different circumstances, much like we do with words,” she said.
Thailand Tree Apes Use Song As Warning (AP)
Check out this Hylobates lar sound gallery (WAVs). There’s also a video gallery (MOVs); both are from the Gibbon Research Lab.