* Bark: They love the bark of trees, especially aspen, willow, and birch.
* Twigs: They eat the tender twigs and leaves of these trees.
* Herbs: They also graze on aquatic plants like water lilies and cattails.
* Roots: They eat roots, especially in the winter when other food sources are scarce.
They are important to the ecosystem because they create dams and lodges that provide habitats for other animals, and their gnawing on trees helps to create openings for new growth.