Metabolic adaptation of the beaver (Castor canadensis Kuhl) to the Arctic energy regime ...

• Main Author: Aleksiuk, Michael
• Format: Text
• Language: English
• Published: University of British Columbia 2011
• Subjects: Arctic; Mackenzie Delta; Northwest Territories
• Online Access: https://dx.doi.org/10.14288/1.0104180; https://doi.library.ubc.ca/10.14288/1.0104180

The beaver (Castor canadensis Kuhl) is subjected to a widely fluctuating energy regime in the northern portion of its distribution. During the summer the animal has free access to an abundant food supply in the form of growing plant material, while during the winter the food supply is limited to a store of cached saplings. The working hypothesis of this study was that seasonal shifts occur in energy expenditure such that it is highest during the summer when an abundant food supply is readily available. In the Mackenzie Delta, Northwest Territories, growth was found to be rapid in the summer and absent in the winter. A winter weight loss characterized immature animals. Fat was deposited in the autumn, maintained during the winter and mobilized in the spring. Animals were lean during the summer. Thyroid gland weights were high in the summer and low in the winter. It was concluded from these data that metabolic energy expenditure is high during the summer and low during the winter. A consideration of possible ...