Busy Beaver at Mirror Lake

April 09, 2013 Posted by: BW - Volunteer Interpreter

Observant visitors to Mirror Lake over the past month may have noticed evidence of beaver (Castor canadensis) activity. Several cottonwood trees around the main reflection pool are showing the toothmarks of gnawing by beavers. The beaver is the largest rodent in our area and it lives in and around water. Master civil engineers of the animal world, a beaver will often construct a house, known as a lodge, or a dam out of logs and brush. These persistent fellows can have quite an impact on the immediate area around where they live. Of course, they will only stick around as long as there is food available. That food is mostly the inner bark, or cambium, of cottonwoods, aspens, and willows. In the Sierra, scarce food may force beavers to shift to a new territory every couple of years. The fate of the beaver at Mirror Lake is anything but certain. By most accounts, although beaver was common in the Central Valley, it was not historically present in the higher elevations of the Sierra. Park biologists are aware of the increase in activity in the park and are monitoring the progress. It remains to be decided whether this non-native species can be controlled, or we will have to tolerate its work.

Tree trunk gnawed on by beaver

.Beaver evidence at Mirror Lake.


Nature Scene, Yosemite Valley, BW

Last updated: April 9, 2013

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