This unassuming, semiaquatic rodent is seen as a nuisance by some but in reality, beavers are significant players in the health of ecosystems and are even vital in stopping wildfires. In addition to providing habitat and a source of water, the ponds and wetlands that beavers create develop a deep level of groundwater that has numerous benefits for the surrounding ecosystem.
Beavers are the largest rodents in North America and the second largest in the world (with capybaras in Australia being the largest). They weigh 40-60 pounds and their stocky body helps conserve heat. One of the most iconic features of a beaver is its large, orange incisors; like other rodents, these incisors also continuously grow throughout a beaver’s life and the constant chewing and gnawing of wood helps keep the teeth sharp and filled down. The orange shade comes from the iron enamel on the teeth, which helps make a beaver’s incisors incredibly strong.
Their herbivorous diet includes leaves, woody stems, aquatic plants, and the same building materials they use for building dams and lodges (wood from poplar, aspen, willow, birch, and maple trees). Beavers also form strong family bonds and are rather social creatures. Groups of beavers usually include a breeding pair, kits (baby beavers), and yearlings, the surviving offspring from the previous year. Communication between beavers includes tail slaps on the surface of the water, various vocalizations, and depositing scents along the edge of their territory. These scents can come from the castor and oil glands that beavers have near their anus. Castor is a very thick, pungent liquid that’s used for scent marking while the oil glands help waterproof a bear’s coat.
Rodents of Unusual Size
Tens of thousands of years ago, the flora and fauna of North America looked very different than it does now. Animals were larger, landscapes were still developing, glaciers melting and eroding away at the land, among many other things. One such difference? Beavers were significantly larger than they are today. There have been many fossils of the giant beaver found across eastern North America but one fossil was recently found in the Yamhill River in Oregon. These giant beavers seem to have been 5-7 feet long, weighed 120-220 pounds, and went extinct roughly 12,000 years ago.
Habitat and Range
Beavers are found in much of North America, except for areas like the American Southwest or far north near the Arctic Ocean. While they do regularly traverse land and water alike, beavers are much more graceful in the water, which is why they thrive in and around streams, creeks, and ponds. They can swim up to 6 miles an hour, stay submerged for up to 15 minutes at a time, and see underwater thanks to their transparent membrane that’s pulled over their eyes for underwater work.
Because of these semiaquatic traits, beavers are able to escape predators a lot better in water than on land, which is why they build dams across streams and creeks to create a pond (and ultimately, a “beaver lodge”). Beaver dams are made from trees, branches, grass, rocks, and mud and help slow down the stream/creek. Inside the resulting pond is a beaver lodge that provides a safe place for beavers to sleep, raise their young, and hide from threats. These dome-like lodges are made with similar materials as dams but can rise 6.5 feet or more and be almost 40 feet in width. The lodges usually have an underwater entrance (or two) but the actual living space is above water and well-insulated.
As a keystone species, modern beavers are absolutely vital for the areas they live in and are one of the few animals that actively modify their environment to suit their needs, as the dams they instinctually create ultimately result in ponds, wetlands, and deep levels of groundwater. These areas also provide a habitat for plants, other animals, and insects. Additionally, the wetlands they create have actually been known to be a safe haven from wildfires in some areas, as fires can’t always cross the soggy areas created by beavers.
For some, beavers can be a nuisance, as they seemingly cause more trouble than good. An article about a beaver relocation project in 2019 quoted a man asking what good beavers do, as “they’re always clogging up culverts and being a pain in the ass”. In fact, this sentiment is, unfortunately, fairly common; in 2018, for example, the USDA killed more than 23,000 beavers that had been in conflict with humans. Beaver relocation projects do exist, including in Washington state, and while they are not typically hunted for their pelts anymore, the fact remains that society has a long way to go in regard to how we view beavers.
Ultimately, beavers are so much more than a nuisance and are actually incredibly valuable animals in many areas. The ponds and wetlands that directly develop because of the dams that beavers build create habitat and safe haven for plants and other animals. Plus, these areas also develop a good groundwater level that helps keep streams flowing and provides water for people and agriculture. While you may not be a fan, it’s hard to ignore the immense good that beavers provide.