Beavers are semi-aquatic rodents renowned for their engineering skills in building dams and lodges. Their diet plays a significant role in their survival and impact on wetland ecosystems. Understanding what these herbivores consume offers insights into their adaptability and contributions to shaping the landscapes they inhabit. Their food choices are driven by nutritional needs and seasonal availability.
Woody Vegetation: Their Mainstay
Woody plants constitute a primary component of a beaver’s diet, particularly the inner, nutrient-rich layers. Beavers primarily consume the cambium, the soft, actively growing tissue just beneath the bark, along with twigs, leaves, and small branches. They eat the softer, more digestible parts that contain essential sugars, starches, and other nutrients, not the hard wood itself. Their powerful incisors are designed to access these layers, and specialized microorganisms in their guts assist in digesting plant cellulose.
Beavers prefer certain deciduous tree species due to their palatability and nutritional content. Aspen is often a top choice, alongside willow, birch, maple, cottonwood, poplar, and alder. These softer woods are easier for beavers to fell and process. While they generally prefer deciduous trees, beavers may consume conifers like pine or fir if other food sources are scarce. Conifers are less preferred for food and often used for building instead. The inner bark and young shoots provide necessary energy for these active animals.
Aquatic and Herbaceous Plants
Beyond woody vegetation, beavers supplement their diet with a variety of aquatic and herbaceous plants, especially during warmer months. They frequently eat water lilies, pondweed, cattails, sedges, and rushes, which are abundant in their wetland habitats. Water lilies can be a significant part of their diet, providing protein and sodium. Beavers also consume herbaceous plants found near water sources, including grasses, clover, and ferns.
These non-woody plants offer a readily available and easily digestible food source. While not their primary wild diet, beavers near agricultural areas may opportunistically feed on crops such as corn, grains, or vegetables if accessible. This consumption is usually opportunistic, occurring when crops are close to water bodies or natural food sources are limited.
Seasonal Dietary Shifts
A beaver’s diet undergoes changes throughout the year, adapting to the availability of different food sources. In spring and summer, when fresh vegetation is abundant, beavers consume a wider array of herbaceous and aquatic plants. During these warmer months, actively growing plants become a more substantial part of their diet, providing easily accessible and nutritious greenery.
As fall approaches, beavers transition their diet to primarily woody vegetation, focusing on bark and twigs, in preparation for winter. This shift is essential for their survival during colder periods when herbaceous and aquatic plants become scarce or inaccessible. Their reliance on stored woody material becomes important when surface foraging is difficult or impossible.
Food Collection and Storage
Beavers exhibit distinct behaviors for collecting and storing food, especially in preparation for colder seasons. They fell trees and cut branches not only for building their lodges and dams but also to access food. The branches are stripped of their nutritious cambium and bark, which are consumed, while the remaining wood is often incorporated into their structures.
Their creation of underwater food caches near their lodges is a key behavior. These caches, initiated in the autumn, consist of branches submerged and anchored to the bottom of the waterway. These underwater stores provide a readily accessible food supply during winter months when ponds are frozen and surface foraging is impractical. Beavers can then swim under the ice to retrieve branches from their cache, ensuring a consistent food source.