The Biggest Beaver Dam in the World

The biggest beaver dam in the world sits in a remote area of Wood Buffalo National Park in northern Alberta, Canada. It is nestled in dense forests and marshlands about 120 miles northeast of Fort McMurray. Jean Thie, a Canadian ecologist, was using Google Earth and NASA satellite images when he located the dam while he was researching how quickly permafrost was melting. The dam is visible from outer space. Beaver dams are some of the only structures made by animals that can be seen from space. Coincidentally, the beaver is Canada's national symbol.

Beaver dams serve as habitats for these mammals, and they also provide protection from predators. The dam design forms pools of water that create passageways for food and building materials. Also, the dam causes water to back up so it freezes only on the surface in the winter. Thus beavers can keep their food, such as stick bark and water plants, under the water year round. Animals other than beavers, such as fish, ducks, frogs, herons and turtles, use the ponds created by dams as their habitats.

The biggest beaver dam in the world is about 2,800 feet long, which is roughly the same length as eight football fields. By contrast, typical beaver dams measure between 32 and 320 feet long. Dams consist of tree logs, branches, twigs and mud. Several generations and numerous families of beavers have been building the massive structure in Canada since the middle of the 1970s. Scientists can tell how old it is not only by its vast size, but also by observing and dating its materials. Lush vegetation such as green grass surrounds and covers the dam structure.

Before Thie discovered the dam in Alberta, Canada, and it was dubbed the biggest in the world, a dam in Three Forks, Montana, measuring more than 2,100 feet, held the record for the world's largest. Beavers are making a comeback and repopulating various areas of Canada where their ancestors previously lived, after centuries of being hunted.

Beavers continue to add to the huge dam they've already built in Alberta, Canada, so its size is growing over time. A smaller dam sits near each end. In the future, all three of these dams might be connected with one another. This would make the impressive structure that much larger.