Belugas, nicknamed “sea canaries” by early whalers, are amongst the most vocal cetacean species. Yet the function of their calls, the development of their extensive repertoires and the role of vocal learning are poorly understood. Click on the spectrogram below to hear what a herd of juvenile male belugas in the St. Lawrence River Estuary sound like.
Vocal Development in Beluga Calves
Valeria Vergara studied the vocal development of a beluga calf, Tuvaq, born in 2002 at the Vancouver Aquarium to understand the development of beluga calls. Valeria discovered that the first sounds a beluga calf makes after birth are low energy, broadband pulse trains that sound like knocking. The calf’s calls gradually develop and strengthen in frequency to resemble the adult buzz-like pulse trains. Valeria also discovered that beluga calves are not born knowing how to whistle. At two weeks old Tuvaq produced his first rudimentary whistle and slowly perfected it with age.
Function of Beluga Calls
Belugas produce an extensive repertoire of calls, whistles and clicks, but the function of these calls was unknown. Valeria looked at the context-specific use of different call types to understand the function of certain beluga calls. She correlated the recorded sounds produced by the group of belugas at the Vancouver Aquarium with observed behaviour and context. Valeria classified 28 distinct call types. Click on the links below to listen to some of the different sounds.
Vocalizations used to establish contact or maintain group cohesion
Vocalizations produced during situations of stress
Vocalizations produced during aggressive interactions
Highly variable, non-stereotyped calls used during bubble play
One particular call-type was repeatedly used and easily isolated in recordings. Valeria classified this broad band pulsed call as the Type A-call or the “contact call”. This call was used predominantly during the birth of a calf and various situations where one beluga was separated from the other whales. Thus the contact call is used to establish contact or maintain group cohesion. Valeria verified the existence and context of the Type A-call in the repertoire of belugas in the wild; in the St. Lawrence River Estuary beluga herds and the Hudson Bay beluga herds. Click on the video below to watch the interactions between Tuvaq and his mother Aurora. You can see when Tuvaq vocalizes because he produces a stream of bubbles from his blowhole.