It is well known that animals use song as a way of attracting mates, but researchers have found that gibbons have developed an unusual way of scaring off predators — by singing to the predators.It is well known that animals use song as a way of attracting mates, but researchers have found that gibbons have developed an unusual way of scaring off predators — by singing to them.
Gibbon and baby. (Image courtesy of Jim Zuckerman, Gibbon Conservation Center)
Literally singing for survival, the gibbons appear to use the song not just to warn their own group members but those in neighbouring areas.
What is more is that fellow gibbons understand them.
Gibbons are renowned amongst non-human primates for their loud and impressive songs that transmit over long distances and are commonly used in their daily routine when mating pairs ‘duet’ every morning. Songs in response to predators — mostly large cats, snakes and birds of prey — have been previously noted, but no extensive research into its purpose or understanding by other gibbons has been done until now.
The researchers were able to identify individual gibbons according to their voice and describe gibbon songs as a ‘crescendo of notes’, formed by combining up to seven notes — including ‘wa’, ‘hoo’, ‘sharp wow’ and ‘waoo’ — into more complex structures or ‘phrases’.Much like the seven notes of ” sa,ri.ga,ma,pa,da,ni,” of the Indian classical music.
The researchers wanted to establish whether there were any differences between the typical duetting morning song and that delivered in response to a predator. They noted subtle differences between the two songs, particularly in the early stages (first ten notes) of the song, which would be important in the case of predator encounters. Songs usually begun with a series of very soft notes, audible only at close range, but which rapidly changed into louder notes heard over long distances.
They said, “We found that gibbons produce loud and conspicuous songs in response to predators to alert kin, both near and far — since gibbons frequently change group compositions, neighbouring groups often consist of close relatives. We found that gibbons appear to use loud ‘long-distance’ calls to warn relatives in neighbouring areas and that those groups responded by joining in the singing, matching the correct predator song, demonstrating that they understood the difference between calls.”
“Not unlike humans, gibbons assemble a finite number of call units into more complex structures to convey different messages, and our data show that distant individuals are able to distinguish between different song types and understand what they mean. This study offers the first evidence of a functionally referential communication system in a free-ranging ape species.”
“Finding this ability among ape species, especially gibbons who in a sense bridge the evolutionary gap between great apes and monkeys, could shed light on when this ability developed in the primate lineage.”