Beavers are rodents recognized for their significant influence on aquatic environments. These animals are entirely herbivorous. Their feeding habits, combined with their engineering abilities, play a considerable role in shaping the ecosystems they inhabit. Understanding what beavers consume provides insight into their natural behaviors and their broader ecological impact.
The Core of a Beaver’s Diet
Beavers primarily consume woody plants, focusing on the inner bark, known as the cambium layer, along with leaves and twigs. The cambium is a soft, nutrient-rich layer found just beneath the outer bark, and it is a preferred food source for beavers. They target deciduous trees with soft wood and high nutrient content. Common examples of trees in their diet include aspen, willow, poplar, birch, alder, maple, and cottonwood.
Beyond woody vegetation, beavers also consume a variety of herbaceous and aquatic plants. Their diet can include water lilies, cattails, sedges, grasses, ferns, and skunk cabbage. They do not eat fish or any other animals. Their large, chiseled incisors are adapted for gnawing on wood, not for consuming meat.
Seasonal Changes in Food Preferences
A beaver’s diet changes throughout the year, adapting to the availability of different plant materials. During the warmer months of spring and summer, their diet shifts to include a higher proportion of herbaceous plants, tender shoots, and leaves. Aquatic plants, such as water lilies and various grasses, become important during this period. This allows them to capitalize on abundant, fresh vegetation.
As autumn approaches and winter sets in, beavers transition to a diet primarily composed of woody materials. They rely on the bark and stored branches of deciduous trees. To prepare for winter when food is scarce and water bodies may freeze, beavers create underwater food caches. These caches consist of branches and woody stems piled near their lodge, providing a readily accessible food supply beneath the ice.
How Diet Shapes Beaver Habitats
The foraging activities of beavers significantly influence their surrounding environment. Their need for woody plants leads them to fell trees, which in turn provides materials for constructing their dams and lodges. This tree-felling behavior can alter forest composition, as beavers often selectively cut certain species, creating openings in the woodland canopy. These open areas can allow more light to reach the forest floor, promoting the regeneration of understory vegetation.
Beaver dams, built from felled trees and other plant debris, impound water, leading to the formation of ponds and wetlands. These newly created aquatic habitats expand water storage, enhance groundwater levels, and can help filter water by trapping sediment. The presence of beaver-created wetlands supports a wide array of other species, including fish, amphibians, and waterfowl, by providing diverse food sources, shelter, and breeding grounds.