No dam needed thank you very much!

The beaver floated there with just the top half of its head sticking up out of the water and stared and stared and stared. In the early twilight, it was menacing in its constant resolute presence. It wanted the pool to itself and was communicating a clear message, “Be gone human intruder.” Negotiation about who would use the pool this evening seemed out of the question despite the caddis flies that were enticing trout to rise.

The usual image of a beaver is of an animal that lives in its lodge in the center of a small pond formed behind its stick dam. That is not always the case. Beaver only build dams to enlarge the underwater habitat to insure it will remain open in winter. Beaver also live in riverbank dens. The deep water of a permanent river pool provides adequate river bottom storage for winter food and underwater access to the den secure from predators, no dam needed thank you very much.

The beaver is the largest rodent in North America with a scientific name Castor canadensis, descriptive of the castor glands located near the base of its tail. Castor is a strong-smelling, oily substance spread by preening to waterproof the beavers’ fur. Native Americans called the beaver the sacred center because when beaver do dam small streams much of the flooded area becomes wetlands with biodiversity that rivals tropical rain forests, creating rich habitats for other mammals, fish, amphibians and birds.

Beavers live up to 12 years in the wild and continue to grow throughout their lives. They can reach 4 feet in length including tail and weigh up to 100 pounds. Their ancestors, a million years ago during the era of the mastodons and mammoths, were even larger. The beavers that inhabited Eurasia and North America measured 9 feet in length including tail and weighed as much as 800 pounds. Fortunately, the beaver contesting for the pool this evening was smaller than that.

The beaver has a compact rotund body with short legs making it ungainly and slow on land. When threatened it can run in an awkward bounding gallop, but in a race to escape over any distance, a predator can run a beaver down. If cornered on land, a beaver will defend itself by standing on its hind legs, hiss, growl and lunge at its attacker. Their sharp incisor teeth allow them to put up a spirited defense, but bear, wolves, coy dogs and coyote will take beaver.

Not so in the water. The beaver is a powerful swimmer, both under water and on the surface attaining speeds of 5 miles per hour. The beaver is perfectly adapted to its watery world as they can close a transparent membrane over their eyes for protection that allows them to see as well under the water as on land. Its nostrils and ears close under water too. The beaver’s hind feet are large, webbed with five long clawed toes and are used to propel itself in the water with occasional steering aid from its tail. Its forepaws that skillfully carry the sticks, stones and mud they use in their construction projects are small, dexterous, without webs, and the five toes end in long sharp claws.

A beaver takes only one mate for life and a pair will have one litter, averaging three kits, each May or June following a 100-day gestation period. Both parents care for the kits and although kits are furred, have teeth, can see, walk and swim when born, they generally do not venture out of the lodge for at least a month. Yearling kits act as babysitters for the new litter while the two-year-olds leave home each spring to find their own territories to insure the family does not overpopulate an area.

While some beaver behavior is instinctive, they also learn by experience according to Dr. Donald Griffin, the father of animal cognition. An experience in point happened on a spring fishing trip. Although the strong April sun had melted the ice from the middle of the small beaver pond, it still had ice ringing its shore. This beaver was obviously tired of winter as it would swim to the ice, chisel out a dinner plate sized piece with its teeth, push it into the center of the pond and then wallop it with its tail. After three hard whacks it would turn, inspect its handiwork and if satisfied with the disintegration of that piece would go to bite off another piece of ice and do it again. Dark came before the pond was ice-free but you knew that beaver would be back at it tomorrow.

Back on the river, the beaver won the twilight staring contest and rising trout or not, it was time to walk on. But before the pool was out of sight, the beaver slapped its tail once, gently, and three members of its family, including two kits, slid out of the riverside den and joined it in the water. Beaver are not concerned if you sit silent on the shore and watch them so if you have never taken the time to watch a beaver family, you are missing a tranquil wonder.
David L. Deen is Upper Valley River Steward for the Connecticut River Watershed Council. CRWC is celebrating over 60 years as a protector of the Connecticut River.