Friday, April 22, 2016

Tracking Beaver

Canadian Beaver - Castor canadensis

The Canadian Beaver is the second largest rodent in the world.

Good beaver tracks are uncommon because the prints are usually wiped out by either the heavy flat tail or by the tree trunks and branches that the animal drags to the water.

The beaver has five toes on the front and hind feet but only three or four usually register. 

The impressions of the large broad nails are visible in the left hind print in the photo below.

The quarter-inch incisors of a beaver can cut down a five-inch willow in three minutes! Beavers strip the bark to access the nutritious inner cambium layer.

The protective wire placed around this aspen was not much of a deterrent for a hungry beaver.

The photo below shows the stumps of numerous aspen cut down last year and dragged into the water for use during construction of a lodge.

Once a beaver starts to cut down trees in a grove, these natural engineers tow the trunks and branches to the water over the same trail. This technique clears the pathway and forms channels with progressively lower resistance to drag, and makes the process faster and more energy efficient. The photo below shows a drag channel over the shore and a typical notch at the edge of the water.

Naughton D. The Natural History of Canadian Mammals. UofT Press. 2012.
Rezendes P. Tracking and the Art of Seeing. How to Read Animal Tracks and Signs. Firefly Books Ltd. Willowdale, Ontario. 1999.

No comments: