North American Beaver
North American beavers are the second largest rodents in the world (after the capybara) and the largest in North America. It is one of the two extant beaver species, the other being the Eurasian beaver. Neither of these two species is closely related to the mountain beaver, also found in North America.
|Scientific Name||Castor canadensis|
|Also known as||Beaver, American beaver, Canadian beaver|
|Description||Size: Head-body length is around 29-35 in (74-90 cm), with the tail being adding 7.9-13.8 in (20-35 cm)
Weight: They weigh about 35-69.5 lbs (16-31.5 kg)
Color: They have two layers of fur, the outer layer ranges from chestnut to an almost black, while the inner layer is a dark grey
|Distribution/Range||Throughout North America with exceptions in the Arctic tundra, peninsular Florida, and the deserts of the southwest; also introduced to Patagonia (Argentina and Chile) as well as in European nations like Finland|
|Habitat||Present near ponds, lakes, and streams|
|Sounds & Communication||Makes a low-pitched groaning sound; it slaps its flat tail in the water to signal danger; mark its territories with a musk-like substance called castoreum, which is secreted from anal scent glands known as castors|
|Lifespan||10-20 years in the wild|
|Diet||Cambium and barks of maple, willow, alder, birch, beech, poplar, and aspen trees, in addition to this, they also feed on roots, buds, and aquatic vegetation; they even eat cellulose, a substance that no other mammal can digest|
|Adaptations||They have certain microorganism in a sac (cecum) between their small and large intestines that help in digesting cellulose; their bodies are shaped for an aquatic lifestyle, with webbed hind feet that help in swimming, and a scaly, flat tail aiding in propulsion and steering; the two layers of fur plus a thick fatty layer under the skin gives them insulation in freezing waters; closeable flaps prevent water from getting inside the ear and nose; a nictitating membrane forms a transparent eyelid to ensure uninterrupted vision underwater; the castoreum is used to waterproof its fur; their large skull and teeth help to cut through hard woods like those of oak and maple; large claws help them to dig, as well handle food with ease|
|Predators||Juveniles are vulnerable to wolves, wolverines, bears, otters, lynxes, and fisher; adults are not regularly preyed upon because of their size|
|IUCN Conservation Status||Least Concern|
North American beavers are nocturnal, being active mostly during the night. They are social animals, living in family groups of up to 8 individuals. They are territorial and do not allow other families to encroach upon their territory. Their homes or ‘lodges’ are made out of twigs, rocks, mud, and sticks in streams and lakes. The lodges may touch land or be surrounded with water. They build dams and make their lodges in the resulting artificial ponds. The primary purpose of a dam is to create a haven to stay safe from predators. They are monogamous.
Mating & Reproduction
The mating season for the northern population of North American beavers is between January and March, while that for the southern population is between November and December. A litter of 1 to 4 young beavers, called kits, are born after a gestation period of 105-107 days. Kits are born with full fur, and with their eyes open. They can start swimming after only 24 hours of their birth.
The kits are expelled from their natal colony at around 2 years of age. It is around this time that they make colonies of their own. Both genders reach sexual maturity at approximately 3 years of age.
- These rodents are the state mammal of Oregon. They are also one of the national animals of Canada, sharing the status with the Canadian horse.
- This species is an example of Bergmann’s rule, with northern populations being larger than their southern counterparts.