The beaver is one of the world’s most unique animals in that it can fell and utilize whole mature trees as food and building resources; there are few plants they cannot digest; and their diet can include several plant species that are poisonous to humans and other animals. Beavers are opportunistic generalist herbivores that can eat bark, twigs, shoots, leaves of woody plants (mainly broad-leaved species), herbaceous and aquatic plants, fruits, and crops. There are over 300 plant species recorded in their diets. This chapter discusses typical foraging behaviours, central-place foraging, processing and felling of woody species, preferred species, diet variations, and seasonal variations in diets. Plant responses to beaver foraging and physiological defence of plants will also be central topics in this chapter.