Terrestrial predation by polar bears: not just a wild goose chase
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Behavioral predictions based on optimal foraging models that assume an energy-maximizing strategy have been challenged on both theoretical and empirical grounds. Although polar bears (Ursus maritimus) are specialist predators of seal pups on the Arctic ice pack, the use of terrestrial food sources during the ice-free period has received increased attention in recent years in light of climate predictions. Across a 10-day period of observation, we documented between four and six individual polar bears successfully capture at least nine flightless lesser snow geese (Chen caerulescens caerulescens) and engage in at least eight high-speed pursuits of geese. The observed predatory behaviors of polar bears do not support predictions made by energy-optimizing foraging models and suggest that polar bears may frequently engage in energy inefficient pursuits of terrestrial prey. Further study of the nutritional needs and foraging behaviors of polar bears during the ice-free period is warranted, given that polar bears are predicted to spend more time on land as climate change advances.
KeywordsOptimal foraging Diet choice Predation Energy budget Chen caerulescens Ursus maritimus
We graciously thank Ryan Choi for his superior assistance with video and image editing. Christa Mulder provided comments on an earlier draft. DTI received support for this project from the S. J. and Jesse E. Quinney Foundation and Delta Waterfowl.
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