Whistle a happy tune

While it is common knowledge that dolphins communicate through whistles, clicks, and screams, most perhaps do not realise how complex their communication is thought to be. This thought stems from the knowledge of dolphin call repertoires, high level of intelligence, and ability to learn and replicate other vocal cues – not just a pretty face! Dolphins use vocal communication, especially whistles, during play, aggressive interactions, male-male competition for females, for social cohesion, and calf discipline, among others. This use of whistling as a means of communication is known as variant whistling, which means the whistles are not individual specific, can change over time, and are produced, as mentioned, in a wide range of social contexts. Dolphins do not only use vocal acoustic cues to communicate, they also use non-vocal acoustic cues which can include tail slapping on the water surface, pectoral fin slapping either on the water surface or onto their own body, and jaw claps.

There has been research suggesting that dolphins produce a signature whistle, which unlike variant whistles, are individual-specific, stable over time, and are primarily used for keeping the group together. A signature whistle can be defined as “a learned, individually distinctive whistle type in a dolphin’s repertoire that broadcasts the identity of the whistle owner”. Signature whistles are thought to be used for individual recognition, primarily produced when individuals are out of visual contact. High occurrences of signature whistles have been seen during reunions of mothers and calves. Dolphins have even been known to copy the signature whistle of other individuals in the group, using it as a way to address a specific individual. However, there has been other research done in which dolphins did not display the production of clear individually-unique signature whistles, instead producing a predominant and shared whistle with subtle individually unique variations.

To hear the variant whistles and other sounds of dolphins, and whales, in our area visit www.conserbio.org.

Written by: Minke Witteveen

For further reading:

• Gregg, J. 2014. How do dolphins communicate? Accessed: 01-03-2016. URL: http://www.dolphincommunicationproject.org/index.php/2014-10-21-00-13-26/dolphin-communication
• Janik, V.M. and Sayigh, L.S. 2013. Communication in bottlenose dolphins: 50 years of signature whistle research. Journal of Comparative Physiology A 199: 479-489.
• McCowan, B. and Reiss, D. 2001. The fallacy of ‘signature whistles’ in bottlenose dolphins: a comparative perspective of ‘signature information’ in animal vocalisations. Animal Behaviour 62: 1151-1162.