What Do Beavers Eat? Bark, Twigs and Water Plants

What part of a tree do beavers eat?

When a beaver cuts down a tree, it is after the food just beneath the rough outer bark. This thin, moist layer (the cambium and inner bark) carries sugars and nutrients and is much softer and more nourishing than wood. Beavers also eat the buds, leaves and thin twigs at the tips of branches.

A beaver holds a stick in its front paws and turns it like corn on the cob, peeling off the bark with its incisors. The bare, white sticks left behind are a sure sign of beavers. Those peeled sticks, and larger logs, are then used to build and repair dams and lodges. Learn more about the builder in our North American beaver profile.

Which trees do beavers prefer?

Beavers are choosy. They pick plants by taste, smell and size, and they will travel past less popular trees to reach their favorites.

Beavers usually cut small trees, often less than 15 cm (6 in) across. A beaver can fell a tree of that size in under an hour. They can bring down much larger trees, but this can take hours of work over several nights. Beavers cut only near water if they can, because they are slow and exposed on land.

Water plants and summer food

In spring and summer, beavers switch much of their diet to soft green plants, which are easier to digest and richer in protein than bark. They graze on water lilies, pondweeds, cattails, sedges, grasses, ferns, herbs and the fresh leaves of shrubs. In northern areas, water lilies are one of their most important summer foods; beavers eat the leaves, flowers and thick underground stems.

Near farms, beavers sometimes eat crops such as corn. They also dig up roots and tubers along the water’s edge.

What do beavers eat in winter?

Beavers do not hibernate, so they need food all winter. In regions where ponds freeze over, families prepare in the fall by building a food cache. They cut branches and push the cut ends into the mud at the bottom of the pond, close to the lodge. The pile can grow so large that its top sticks up through the ice.

The cold water keeps the bark fresh for months. During winter, beavers leave the lodge through an underwater entrance, swim under the ice to the cache, pull off a branch and bring it back to eat inside. This is one reason beavers build dams: they need water deep enough not to freeze to the bottom, as explained in why do beavers build dams? In milder climates, beavers keep foraging on land and store less food.

How do beavers digest bark?

Bark is full of cellulose, the tough material in plant cell walls that most animals cannot digest. Beavers have a long intestine and a large cecum, a side pouch of the gut filled with bacteria and other microbes. These microbes ferment the cellulose and help the beaver extract energy from it. Beavers can digest roughly 30% of the cellulose they eat.

Like rabbits, beavers are known to re-eat some of their soft droppings, which gives the food a second pass through the gut and recovers more nutrients. The powerful, constantly growing front teeth also matter: they are reinforced with iron, which explains why beaver teeth are orange.

Do beavers eat fish or meat?

No. Beavers are strict plant eaters. The belief that they eat fish probably comes from mixing them up with otters, which share the same rivers and ponds. In fact, beaver ponds usually help fish by creating deep, cool pools and rich feeding grounds for young trout and salmon.

What do baby beavers eat?

Beaver kits are born in spring with fur and open eyes. For their first weeks they drink their mother’s milk, which is unusually rich in fat for a rodent. Within about two weeks they begin to nibble soft leaves and plants, and their parents and older siblings carry fresh food into the lodge for them. Kits are usually weaned by about three months old.

By late summer, young beavers forage for themselves near the lodge, and in their first fall they help gather branches for the family’s winter food pile. Learning which plants to eat, and where to find them, is part of the two years they spend with their family.

Eurasian beaver diet

The Eurasian beaver of Europe and Asia eats much the same foods: willow, aspen and birch bark in the colder months, and water plants, grasses and herbs in summer. Many Eurasian beaver populations do not build large underwater food caches and instead keep foraging on land in winter.