Beaver are common and abundant throughout the entire Northeast. They are an important keystone species in that their dam building activities create habitat for many fish, wildlife, and plant species. The beaver is the largest native rodent in North America with adults weighing 40 to 50 pounds or more. The most distinguishing feature is its large, flat black tail. It is primarily aquatic and can be found wherever water and trees are available. Beavers cut (chew) down a wide variety of trees, and especially prefer poplars, aspens and willows. They also girdle trees (chewing off the bark in a ring around the entire tree near the base), which almost always results in the death of the trees.

Beavers are the engineers of the animal world, building dams and lodges in streams and ponds using nearby trees. These dams create valuable wetland habitats but may also flood roads, destroy crops, damage septic systems, and kill trees in low-lying areas. In rare instances, beavers can contract rabies and may even attack people after being infected by the disease.