Right paw foraging bias in wild black bear (Ursus americanus kermodei)

Abstract

Using field observations of ~15 wild adult black bear (Ursus americanus kermodei) foraging on a salmon stream during two autumns on the central coast of British Columbia, we tested for laterality of forelimb use during lunging and during handling of salmon. Of 288 lunging events observed overall, 53% were non biased, 26% were right-limb biased, and 21% left-limb biased (p = .53 between left and right bias). Among six bears in which we could ascertain individual identity (182 lunging events), there was heterogeneity among individuals (p <.05) of which two were significantly right biased and one significantly left biased (p<.005). Of 186 carcass-handling (pick-up) events, 68% were right-pawed (p <.005) and there was no heterogeneity among five individually identifiable bears (p = .19). There was no forelimb laterality in adjustment of the prey in the mouth or in securing the prey to the substrate. This is the first report of task-specific behavioural lateralisation of a wild carnivore and is suggestive of a right bias (left-hemisphere dominance) in object manipulation.

Keywords:

• Carnivore
• Foraging
• Handedness
• Laterality
• Ursus

Acknowledgements

We thank Dan Klinka for discussion, Marvin Robinson for discussion and logistical assistance, Stan and Karen Hutchings for travel assistance, and the Hartley Bay Band Council for permission to conduct observations in their territory. TER acknowledges the David Suzuki Foundation and the Natural Sciences Engineering Research Council of Canada (operating grant NRC2354) for financial support.