Beavers (Castor canadensis)
are the largest rodent species in North America and weigh 40 to
60 pounds. They are semi-aquatic animals that spend most of their
time in rivers and streams. Beavers are equipped with several
unique features that allow for easy navigation in water. Webbed
hind feet assist in swimming; dense fur acts as insulation in
cold water; ear and nose openings are designed to close when submerged;
and a broad, flat tail functions in swimming, dam building, and
communication.
Beavers are nocturnal social
animals that live in family groups and mate for life. Females
give birth in the spring, usually to three or four kits. Both
parents, as well as year-old siblings, care for the newborns.
At the age of two, offspring leave the family unit in search of
their own breeding territory. The lifespan of a wild beaver is
approximately 10 years.
Beavers create dams to raise
water levels so they can build their homes, or lodges, in the
water. By effectively creating an island with an underwater entrance,
they are protected from many predators. The entrance leads to
dry chambers where beavers sleep, give birth, and store food for
future consumption. These animals may also create burrows in riverbanks.
Beavers eat the leaves, roots,
cambium, and bark of trees such as aspen, willow, and cottonwood.
They also eat clover, apples, corn, grasses, water lilies, and
other aquatic vegetation. A beaver’s teeth will grow throughout
its lifetime; gnawing on trees keeps them from overgrowing.
Beavers have many natural predators,
including: wolves, coyotes, bears, mink, lynx, bobcats, cougars,
raptors (which kill juveniles), and humans. Humans are, in fact,
one of the biggest threats to beavers. Trapping, water pollution,
and habitat loss through drainage of wetlands, are common occurrences
that negatively affect beaver populations.
