Optimum habitats include montane riparian, valley foothill riparian, riverine, lacustrine, aspen, and fresh emergent wetland. In winter, subsists on bark and cambium of trees. In California, aspen, willow, alder, and cottonwood are preferred. Forages mostly on or near streambanks, felling trees and harvesting branches for winter food. Stores branches in lodge or on pond bottom, held in place by mud.
Food preferences vary seasonally.
Lodges and bank burrows constructed for shelter. May construct canals to feeding areas, providing cover while traveling . Builds lodges out of branches and mud, or burrows in muddy banks. Kits born in a nest inside lodge or burrow, which have underwater entrances. Requires permanent, preferably deep, water in rivers, streams, lakes, or ponds, in open to moderately dense riparian forest.