The Seasonal Food Regime of Arctic Beavers

Seasonal variation in food of the beaver (Caster canadensis Kuhl) was examined on the Mackenzie Delta, Northwest Territories, Canada. Leaves and, to a lesser extent, growing tips of willow (Salix spp.) were the main food items during July and August; during the remaining 10 months food consisted of...

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Bibliographic Details
Published in:Ecology
Main Author: Aleksiuk, Michael
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 1970
Subjects:
Online Access:http://dx.doi.org/10.2307/1933662
http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F1933662
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F1933662
https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/1933662
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Summary:Seasonal variation in food of the beaver (Caster canadensis Kuhl) was examined on the Mackenzie Delta, Northwest Territories, Canada. Leaves and, to a lesser extent, growing tips of willow (Salix spp.) were the main food items during July and August; during the remaining 10 months food consisted of the bark of willow (76%), poplar (Populus balsamifera) (14%) and alder (Alnus crispa) (10%). Protein: calorie ratios in the diet were approximately 40 and 8 mg/cal during those two periods respectively. The northern beaver has adapted to low energy availability characteristic of winter by storing food in the autumn and again in the spring, and by intrinsically lowering food intake during the winter. It has adapted to seasonal variation in protein availability by utilizing high—protein willow leaves almost exclusively when they are available. The heavy dependence upon willow, and its resultant removal from the community, can impart a high degree of instability to northern beaver populations.