Interaction between learned and naturally selected features in the design of killer whale calls and their functions

Authors

  • Harald Yurk JASCO Applied Sciences & Coastal Ocean Research Initiative

Abstract

All cetaceans, and particularly all dolphins, rely heavily on acoustic signalling to survive and reproduce. The killer whale or orca is the largest dolphin and occurs in all ocean basins. Killer whales produce stereotyped calls with complex temporal and frequency structure that allow spectrographic distinction into different call components. Call components differ in directionality and attenuation and may be used to synchronize travelling and foraging behaviours by allowing recognition of whales at great distances and identification of the direction of approaching and moving senders. Killer whale communities or populations that avoid social contact may still occupy the same areas (sympatry).  Members of these populations are distinguishable by ecological and social differences such as are prey preferences (fish versus mammals) and social behaviours. Mutually unintelligible call repertoires seemingly are drivers for social segregation. Calls appear to be learned traits transmitted from parent generation to offspring generation in stable matrilineal groups which form the basis of all well studied populations. This preference for social learning is the basis for stable long lasting vocal traditions or dialects and may also influence other stable behaviours such as prey preferences. The stability of dialects can be traced through the observation of acoustic divergence among groups: high dialect similarity among socializing and closely related groups diminishes with social and genetic distance leading to diverse and discrete call dialects among interbreeding clans and among non socializing, non-interbreeding communities. This pattern of selective social learning appears to be the root cause for distinct dialects which allows mate selection to avoid inbreeding and fosters cooperation among clan and community members while it also maintains social segregation and genetic isolation between non-cooperating mammal eating and fish eating populations. It is possible that call structure design together with call dialects allow killer whales to be highly efficient foragers living in tight knit genetically viable social communities at higher densities in a given area than would be possible without ecological segregation.

Author Biography

Harald Yurk, JASCO Applied Sciences & Coastal Ocean Research Initiative

Behavioural Ecologist and Senior Bioacoustician

Published

2016-08-18

How to Cite

1.
Yurk H. Interaction between learned and naturally selected features in the design of killer whale calls and their functions. Canadian Acoustics [Internet]. 2016 Aug. 18 [cited 2021 Dec. 5];44(3). Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3007

Issue

Section

Proceedings of the Acoustics Week in Canada