Present address: Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia.
Killer whale ecotypes: is there a global model?
Article first published online: 9 AUG 2012
© 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society
Volume 88, Issue 1, pages 62–80, February 2013
How to Cite
de Bruyn, P. J. N., Tosh, C. A. and Terauds, A. (2013), Killer whale ecotypes: is there a global model?. Biological Reviews, 88: 62–80. doi: 10.1111/j.1469-185X.2012.00239.x
- Issue published online: 2 JAN 2013
- Article first published online: 9 AUG 2012
- (Received 8 November 2011; revised 6 July 2012; accepted 18 July 2012; published online 9 August 2012)
- killer whale;
- Orcinus orca;
- Southern Ocean;
- eastern North Pacific;
- North Atlantic
Killer whales, Orcinus orca, are top predators occupying key ecological roles in a variety of ecosystems and are one of the most widely distributed mammals on the planet. In consequence, there has been significant interest in understanding their basic biology and ecology. Long-term studies of Northern Hemisphere killer whales, particularly in the eastern North Pacific (ENP), have identified three ecologically distinct communities or ecotypes in that region. The success of these prominent ENP studies has led to similar efforts at clarifying the role of killer whale ecology in other regions, including Antarctica. In the Southern Hemisphere, killer whales present a range of behavioural, social and morphological characteristics to biologists, who often interpret this as evidence to categorize individuals or groups, and draw general ecological conclusions about these super-predators. Morphologically distinct forms (Type A, B, C, and D) occur in the Southern Ocean and studies of these different forms are often presented in conjunction with evidence for specialised ecology and behaviours. Here we review current knowledge of killer whale ecology and ecotyping globally and present a synthesis of existing knowledge. In particular, we highlight the complexity of killer whale ecology in the Southern Hemisphere and examine this in the context of comparatively well-studied Northern Hemisphere populations. We suggest that assigning erroneous or prefatory ecotypic status in the Southern Hemisphere could be detrimental to subsequent killer whale studies, because unsubstantiated characteristics may be assumed as a result of such classification. On this basis, we also recommend that ecotypic status classification for Southern Ocean killer whale morphotypes be reserved until more evidence-based ecological and taxonomic data are obtained.