Amanda Bancroft
Beavers do it big. They’re the second-largest rodents in the world, after capybaras (a South American relative of the guinea pig).
The world’s largest beaver dam, located in Wood Buffalo National Park in Canada, is 2,790 feet long. It’s believed that these beavers started construction as early as 1975! But beavers are not just builders. They create fertile soils, mitigate the effects of drought, reduce evaporation, and their dams filter the water. Their lives are filled with family, risk, and hospitality to their ecosystem communities.
North American beavers put family first. They mate for life, and live in groups from two to ten adults, juveniles, yearlings and sometimes two-year-olds. Males and females share equally in raising young, defending territory, and building dams and lodges. Felling trees for their construction is a risky endeavor. Beavers know just how to chew down a tree so that it falls in the direction of home, but they do occasionally get crushed. It takes them around twenty days to build a lodge, and this is a team effort often involving offspring from previous years who apprentice with the adults in order to learn the beaver carpentry trade. Each spring, mother beavers give birth to three or four kits roughly the size of guinea pigs.
Beaver habitat is riparian zone, and these vegetarians are good creators and maintainers of wetlands. First they create the dam (which they can rebuild overnight if necessary) with mud, stones and timber. Once the water level begins to rise, they turn their attention to building their lodge. Interior rooms are hollowed out after the structure is finished. They take in lodgers who live in the same rooms as the beaver family: muskrats, frogs, insects, deer mice, fungus, and more. This sort of community hospitality is unique.
They can be pests to farmers currently benefiting from fertile land that was once a beaver pond. When beavers return and build a new dam, they cause flooding. But beaver whisperer Michel Leclaire has found that placing a recording of running water where you want beavers to build their dam entices them to build in places convenient for people. Other advice for farmers, road crews and the general public for getting along with beavers can be found on Beavers: Wetlands & Wildlife’s website at BeaversWW.org.
Beavers are mostly nocturnal, so it’s hard to glimpse them. They spend most of their time in or near water where they’re less likely to be attacked by a predator. They can remain underwater for fifteen minutes!
Beavers create a wetland habitat which is great for a plethora of species but not so great for species like the endangered Arkansas darter, a small fish that does not need a beaver pond bringing in predatory species that may eat it. Beaver ponds are also not so great for climate change, contributing a small percentage of methane gas into the atmosphere from their ponds. That’s a pretty small downside for an animal that provides big benefits to North America overall – particularly in areas prone to drought.
Amanda Bancroft is a Master Naturalist and volunteers with her husband Ryan for their solar-powered online educational center on how to make a difference with everyday choices at: www.RipplesBlog.org.
