Frequently Asked Questions About Beaver Dams

How big can a beaver dam get?

The size of a beaver dam varies greatly depending on the landscape. A typical dam on a small stream might be 3 to 5 feet (1 to 1.5 meters) high and 20 to 30 feet (6 to 9 meters) long. However, they can be much larger. In flatter terrain, dams can stretch for hundreds of feet. The largest known beaver dam, discovered via satellite imagery in Wood Buffalo National Park, Alberta, Canada, measures an astonishing 2,790 feet (about 850 meters) in length and is believed to have been worked on by generations of beavers for decades.

Do beavers eat the wood they use for dams?

This is a common misconception. Beavers do not eat solid wood. They use the de-barked logs and larger branches as structural building materials for their dams and lodges. Their food source is the nutritious inner bark layer, called the cambium, as well as the leaves and tender twigs. After stripping the bark for food, they recycle the remaining wood for construction.

What happens if a beaver dam breaks?

A dam breach, often caused by a major flood event, can release a large volume of water downstream very quickly. This can cause temporary flooding and erosion. However, beavers are incredibly resilient and persistent. As soon as the floodwaters recede, the colony will almost immediately begin the process of repairing the breach or building a new dam. Their drive to maintain a stable pond is one of their strongest instincts.

Are beavers nocturnal?

Beavers are not strictly nocturnal (active only at night). They are more accurately described as crepuscular, with their peak activity occurring at dawn and dusk. They may also be active on overcast days and will work through the night. Their cautious nature means they prefer to be active under the cover of low light to better avoid predators.