Beavers are often associated with aquatic environments due to their dam-building and lodge-constructing activities. This connection frequently leads to a common misunderstanding: do beavers eat fish? The definitive answer is no. Beavers are strict herbivores, meaning their diet consists exclusively of plant matter. Their biological makeup and feeding habits are entirely adapted to a plant-based diet, distinguishing them from aquatic predators.
A Herbivore’s Menu
A beaver’s diet is diverse and varies with the seasons, focusing on a wide array of plant materials. During spring and summer, their menu primarily consists of succulent, soft vegetation such as aquatic plants like water lilies, cattails, rushes, and sedges. They also graze on grasses, clover, and various herbaceous plants, which can comprise up to 90% of their summer intake.
As autumn and winter approach, beavers shift their diet to woody vegetation. They primarily feed on the inner bark (cambium), leaves, and twigs of deciduous trees. Preferred species include aspen, willow, cottonwood, birch, alder, poplar, and maple. Beavers also store branches and stems underwater in a “food cache” near their lodge, providing sustenance when ice covers their ponds and fresh forage is scarce. This dietary flexibility ensures they have sufficient energy to sustain themselves through the year.
Why Not Fish?
Beavers are biologically unsuited for a carnivorous diet, lacking the necessary adaptations to catch or digest fish. Their large, orange-colored incisors exemplify their specialized anatomy. These continuously growing teeth are hardened with iron, making them strong and designed for gnawing through tough woody material, not for seizing agile prey like fish. The unique structure of their teeth, with softer dentin behind a harder enamel front, allows them to be self-sharpening as they chew.
A beaver’s digestive system is adapted for breaking down cellulose, a complex carbohydrate found in plant cell walls. They possess an enlarged cecum, a pouch at the beginning of their large intestine, which contains specialized bacteria and fungi. These microorganisms facilitate fermentation, enabling beavers to digest a significant portion of the cellulose they consume. This digestive setup is different from that of a carnivore, which is designed to process animal proteins and fats. The misconception that beavers eat fish likely arises from their aquatic lifestyle, leading to an incorrect assumption about their dietary habits.