Fooling Beavers

 

A beaver dam is a structure built by beavers using branches, twigs, mud, sticks, rocks, and grass. The dam's shape can vary based on the number of beavers and the amount of water in the area. Beaver dams are usually semicircular or crescent-shaped. 

It turns out these dam-building actions can help the environment. They recharge groundwater, filter out sediments, and create habitat for waterfowl, amphibians, fish, and aquatic invertebrates—all while providing ecological services including flood control, drought management, and carbon sequestration. Those are not why beavers build them. A dam stops the flow of water and creates ponds that are safe from predators like coyotes, wolves, and bears, and provide food during winter.

Beaver pairs mate for life and produce one or two pups a year. When pups reach maturity at around two years, they strike out on their own, traveling an average of 3.5 miles in search of new terrain. Over time, beaver populations began to rebound, returning to their historical habitat—much of which included cities. According to a Sierra Club article, park officials are seeing the return of these aquatic rodents as the source of some wrecked landscapes as they have toppled trees, flooded trails and roads, and damaged infrastructure. 

Solutions are to trap the pioneering beavers and remove their dam debris, but they are persistent. Then someone found a way to baffle the beavers into better behavior.

It turns out that beavers build dams instinctively in order to stop the sound of running water. It is an innate quirk of the species. Building a flow device (some are trademarked as Beaver Baffler, Castor Master, and Beaver Deceiver) tricks the beaver into thinking they’ve built the perfect dam by eliminating the noise and sensation of flowing water. They use a long perforated pipe to divert water from the center of a pond out through a hole in the dam and down into the stream. The pipe helps muffle the sound of running water until it’s past the dam, and exclusion fencing on each end of the pipe keeps the beaver from plugging the system. 

Beavers have been a part of the North American landscape for 24 million years, evolving from bear-size rodents into their current form. Indigenous communities coexisted with a population ranging from 60 to 400 million animals and used them for food fur, and castoreum, a sweet-smelling gland excretion used in traditional medicines and—eventually—vanilla ice cream. But it was their fur—with 75,000 to 150,000 hairs per square inch—that nearly led to their downfall. Demand for the warm, waterproof pelts drove much of European exploration and colonization of North America. By the time beaver hats fell out of fashion, only remote pockets of the animals remained.