This is a white-handed gibbon video.
Gibbons Defend Against Predators With Song
By Charles Q. Choi
Special to LiveScience
posted: 23 December 2006
Scientists discovered that wild gibbons in Thailand have crafted unique songs as alarm calls to other gibbons, a discovery that might shed light on the evolution of spoken language.
The sounds that animals make are traditionally thought of simply as signs of their basic mood.
At times, however, animal sounds are used to communicate specific details about the world to others.
For instance, vervet monkeys [see also here] give one kind of call if they see a snake, prompting others to search the ground, and another type of cry if they see an eagle, leading others to watch the sky, explained study team member Klaus Zuberbühler, a psychologist and primatologist at the University of St. Andrews in Scotland. This is known as “referential signaling.”
Relatively little evidence for such a level of communication was seen in more closely related primates in the wild. “It’s been a puzzle,” Zuberbühler said.
Gibbons are known for their loud, elaborate songs every morning, often coordinating in duets with their mates. These can be heard up to miles away through dense forest.
Primatologists led by Esther Clarke of the University of St. Andrews observed white-handed gibbons at Khao Yai National Park in Thailand.
To see how these primates might respond to predators, the researchers built fake animals that resembled typical gibbon predators.
Early primate fossils of Myanmar: here.