Our forest community is host to the American beaver and mountain beaver. The former is the largest rodent in North America – top logging weight averaging 40 pounds – while the latter is half that size.

In fact, the mountain
beaver is not a beaver at all. Known affectionately as “Boomer,” the mountain
variety is referred to as a beaver due to its beaver tendencies. They gnaw
bark and cut off limbs like their American cousins.

The mountain beaver is thought to be the world’s most primitive living rodent
species. They are about a foot long and resemble overgrown hamsters. Their
tails are rudimentary, but they maintain the sharp teeth and claws for
gnawing, digging and climbing.

They are not particular about their diet, feasting on ferns, vine maples,
salmon berry, rhododendrons, dogwoods, maples, alders and conifers – just
about anything that grows in the Mountain community.

Unlike the American beaver, this smaller version does not build dams across
waterways, preferring to burrow into homemade tunnels that can extend 10
feet underground across a territory of two acres or more.

“They are more secretive (than American beavers) and spend most of their
time underground,” said Susan Barnes, Oregon Department of Fish and
Wildlife biologist. “Landowners will sometimes complain they chew newly
planted seedlings.”

But Barnes was quick to point out the benefits far outweigh the shortcomings.
“Their burrowing aerates soil, their scat acts as fertilizer, and their gnawing
becomes space for woodpeckers.”

The American beaver is the hefty cousin that can top 40 pounds into a 3-foot
frame. They are not only master loggers, they are extraordinary engineers.
The nose and ears seal out water, the hind feet are webbed, large incisor
teeth are used to cut down trees and peel bark while eating. They have poor
eyesight but a keen sense of sight and smell. They are territorial and will
mark their areas with a pungent oil called castoreum.

The sound of flowing water is all this beaver needs to stimulate its damming
instinct. Their structures can be as high as 10 feet and stretch more than 150
feet. Utilizing their engineering expertise, they will often leave a leak in their
dam to allow the flow of water, especially during times of high water.

They constantly repair their dams and can rebuild them in quick fashion.

Beavers choosing habitats of calm water – lakes, ponds or marshes – do not
build dams.

Beaver dams provide a deep water hideout from predators, an area to store
food, stay warm, and give birth and raise their young – called kits.

Mates live together for many years, and often for life. They breed between
January and March, have litters of as many as eight kits between April and
June, and the kits are weaned at 10 to 12 weeks of age. Most kits will hang
around until two years old before going off in search of mates and areas to
create new colonies.

Most of the conflicts with beavers are caused by human activity. Barnes cited
roads and houses being built too close to streams and under-sized culverts as
examples.

“But the advantages are many,” Barnes said. “Dam building creates valuable
wetlands and habitats essential to a healthy environment – including habitats
for fish to grow and hide, and basking areas for turtles. Wetlands are like
sponges, absorbing moisture, reducing flooding and providing important
nutrients.”

Back in the 1800s beaver became nearly extinct due to trapping for pelts. The
collapse of the fur market helped rescue the valuable rodents.

A trapping season still exists, from Nov. 15 to March 15. Common predators
include coyotes, owls, cougars and bears. Large numbers of the mountain
beaver are often trapped to prevent damage to newly seeded or planted
commercial forests. Occasionally, they are relocated.

Beaver are not aggressive by nature, but they are not without weapons.

Barnes told The Mountain Times there are a couple incidents that have been
reported on the east coast of beavers having bit the butts of swimmers.

There have been no such incidents reported on the west coast, suggesting our
Mountain beavers have a healthy amount of derriere respect.