Get to Know the North American Beaver

North American Beaver (Castor canadensis) Fun Facts 

  • Beaver are found in 49 of the 50 states, Canada, and Northern Mexico. The only state without a population of native beaver is Hawaii.

  • The beaver is the largest rodent in North America. Their diet is strictly herbivorous and consists mainly of the inner bark of trees, shoots, buds, and aquatic vegetation.  While most beavers weigh 40-70 pounds, large individuals can weigh in at over 100.

  • Beaver are notorious for their dam-building behavior. One of the reasons they do this is to expand their watery habitat to stay safe from predators. On land they are vulnerable, but deep water allows underwater access to their lodges or dens, and they can avoid predation.

  • Beaver are often seen in urban environments because they do not need much to thrive. Clean water and a food source are the two main factors to sustain a beaver population.

  • The beaver’s tail has multiple functions. It is used to swim, to communicate, and to store fat.

  • Beavers have a unique trait in that they can continue to gnaw while being underwater. How do they do this? They have lips that can close behind their large incisors so that water can be blocked while still gnawing.

  • The hair/fur of a beaver is essential for their survival, but also what made them hunted to near extinction. The double coat of the beaver hide was prized by fur trappers. The outer coat consists of longer guard hairs, but the undercoat, sometimes called “beaver wool” is what was used for felting and ultimately the beaver’s downfall. This undercoat can be felted to be waterproof and warm, and was often used to make hats.

  • Beaver are an important keystone species and can dramatically change a landscape. Beaver sites can cycle through forms over long periods of time; pond, wetland, wet meadow, prairie, early successional forest, late forest, and stream which provides habitat for an extraordinary variety of plants and animals. This is all due to their dam-building behavior.

  • Beaver can also improve water quality by slowing water down and allowing solids (natural or from runoff) to sink or filter out. These catch basins are an important aspect of “beaver restoration” projects.

  • Research shows that the landscape of North America was shaped by beavers whose ecosystem engineering skills are being mimicked or employed by scientists to address all kinds of challenges. Beavers can reduce flooding, store water in times of drought, and create salmon spawning habitat and natural firebreaks.

  • Too often they are misunderstood as pests and are trapped, and their habitat is destroyed by humans or overgrazing by ungulates.

Beaver photo courtesy Illinois Department of Natural Resources.