• Sow grizzly with cub trailing her.


    National Park ID,MT,WY


The beaver (Castor canadensis) is a keystone species that affects habitat structure and dynamics through the damming and diverting of streams, and the felling of trees and other woody vegetation. The resulting ponds and flooding help create an environment favorable to willow and aspen, the beavers' preferred winter foods and used in building their lodges. The territoriality of beavers probably deters two colonies from locating within 50 meters of each other, and most streams in the park lack either suitable vegetation or a sufficiently low gradient to provide beavers with habitat, but information about the distribution and number of beaver colonies in the park over time adds to our understanding about the long-term effects of changes in vegetation and climate. Learn More: Beaver Information Continued…

Quick Facts about Beavers in Yellowstone

  • 112 colonies counted in 2011
  • If living on rivers, may build bank dens instead of lodges
  • Average life span: 5 years.
  • Male and female beavers look alike—thick brown fur, paddleshaped tail.
  • Like wolves, beavers live in family groups, which are called colonies. Fewer than 5% of mammals live organized like this.
  • Yellowstone's beavers escaped most of the trapping that occurred in the 1800s due to the region's inaccessibility

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