Dance, gibbon, dance!

Zoo visitors have perhaps already seen how female crested gibbons perform conspicuous sequences of twitching movements involving the rump, arms and legs. This behaviour can be observed in zoos and also in the wild. This video provides a clear impression of the dances of female crested gibbons.

Crested gibbons belong to the family of small apes. There has been little scientific interest in this special display to date. Dr Kai R. Caspar from the Institute of Cell Biology at HHU, Dr Camille Coye from the Institut Jean Nicod in Paris and Professor Dr Pritty Patel-Grosz from the University of Oslo in Norway have now analysed this striking behaviour of the gibbons in more detail and present their results in the journal Primates. They focused on the sequence of movements, rhythm and intentionality -- i.e. the circumstances in which the gibbons perform the dances.

Dr Coye, lead author of the study: "Our examination of video material from various zoos and rescue centres proves that all species of crested gibbons perform these dances. They represent a common and intentional form of visual communication." It is an indicator of the intentional usage of the dances that the gibbons often check during a performance whether the audience is paying attention.

Professor Patel-Grosz: "Only sexually mature females dance. Within species, the dances are evidently primarily used to solicit copulation, but they also occur in a wide range of situations related to non-sexual arousal or frustration and are also frequently directed at humans when performed in captivity in zoos."

The researchers also observed that the dance movements display a grouping structure. Dr Caspar: "They are often organised in groups of up-down or left-right movements and they follow a clear rhythm. Depending on the individual, the movement sequences may vary in complexity."

The researchers can see similarities between crested gibbon and human dances, but presume that they evolved independently of each other. This conclusion is based among other things on the fact that other species of apes do not display this type of behaviour. Furthermore, gibbon dances are also likely to be innate, while human dance is primarily determined by culture. Human dance is also frequently accompanied by music or song, while this is never the case with gibbons.

"The dance behaviour was noticed by chance, but is now being reported from various zoos," says Dr Caspar. Dancing crested gibbons can be seen at Duisburg Zoo and Burgers' Zoo in Arnhem in the Netherlands, among other locations.