Parallel influence of climate on the behaviour of Pacific killer whales and Atlantic bottlenose dolphins |
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Authors: | David Lusseau Rob Williams Ben Wilson Kate Grellier Tim R Barton Philip S Hammond Paul M Thompson |
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Institution: | Lighthouse Field Station, School of Biological Sciences, University of Aberdeen, George St, Cromarty, Ross-shire IV11 8YJ, UK; Natural Environment Research Council Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife KY16 8LB, UK; Marine Mammal Research Unit, University of British Columbia, 6248 Biological Sciences Road, Vancouver, V6T 1Z4 BC, Canada |
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Abstract: | The grouping behaviour of animals is governed by intrinsic and extrinsic factors which play an important role in shaping their social organization. We investigated the influence of ocean climate variation on the grouping behaviour of two widely separated populations of cetaceans, inhabiting north Atlantic and north Pacific coastal waters. The group size of both bottlenose dolphins in the Moray Firth, UK, and killer whales in Johnstone Strait, Canada, varied from year to year in relation to large‐scale ocean climate variation. Local indices of prey abundance were also related both to climate indices and predator group sizes. The cetaceans tended to live in smaller groups when there was less salmon available in both areas which seem to occur 2 years after a lower phase of the North Atlantic and Pacific Decadal Oscillations. These findings suggest that, even in highly social mammals, climate variation may influence social organization through changes in prey availability. |
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Keywords: | Bottlenose dolphin climate influence grouping pattern killer whale mean-field model North Atlantic Oscillation Pacific Decadal Oscillation salmon |
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