Nature's Engineers The Dam Beaver
Do beavers live on Fermilab property?
Yes. Several beavers' lodges can be spotted on Fermilab's site. Since beavers, Castor canadensis, are mostly nocturnal animals, they are rarely seen during the day. But a visitor might find evidence of the existence of about twenty resident beavers.
Why are beavers called "Mother Nature's Engineers"?
Beavers are born knowing how to build lodges and dams. They stand on their hind legs and cut down trees, while balancing on their tail. They cut down as many as 200 trees a year, mostly soft-wood trees such as cotton-woods or willows. This actually helps the groundcrew of Fermilab to curb the growth of unwanted trees. The beavers then start their building by holding large sticks in their mouths and driving them straight into the river bottoms or ponds. Then almost anything that a beaver can find goes into the lodges and dams: sticks, grass, rocks, or even old shoes!
Beavers are fantastic "engineers"! First they build their lodges, which look like six-foot heaps of branches and mud. They gnaw two to five tunnels to be used as entrances and exits. Next, beavers build a dam to raise the water level, which causes water to back up and cover these entrances and exits. The dam is built like a layer cake except that it is held together by mud, not icing, which is smeared on with their paws and noses. Beavers can build a 35-foot long dam in just one week.