beaver behavior Archives - Following Deer Creek

History

In 1805, Lewis and Clark saw beaver dams “extending as far up those streams as [we] could discover them.” Even before the famous explorers, French trappers and traders were drawn to the land teeming with beaver.

The beaver is North America’s largest rodent. Its pelt is waterproof and has a double layer of insulation making it highly desirable for human use. At the height of pelt demand, some estimates claim that between 60-400 million animals were taken.

Fortunately, we have beavers living along Deer Creek!

The beaver method of water retention, stream restoration, and habitat rehabilitation.

Beaver ponds and dams;

reduce erosion
act as a fire break
slow water movement through a watershed, replenishing the water table, reducing the need for irrigation
filter nitrogen and other chemicals that cause algae blooms resulting in oxygen-deprived dead zones
retain sediments, increasing watershed biodiversity

Ponds volume keeps water temperatures cool, necessary for certain fish species

Discord Between Beavers and People

beaver may eat landscape plants and trees within 165 feet of the water’s edge
water pooling on the land will expand
roads and structures may flood
dams plug culverts and drains
animals and wildlife are attracted to the habitats beavers create

In 2017, the USDA Animal and Plant Health Inspection Service killed 81 beavers in California.

Beaver Problem Remediation

install a pond flow device, limiting water rise, eliminating flooding
choose landscape plants that beaver don’t eat
choose plants that resprout after a beaver visit
keep landscape plants distant from the water source

Barrier methods;

wrap large trees with 3 ft. high galvanized welded wire fencing or multiple layers of chicken wire
paint tree trunks with sanded paint ( mix 2/3 cup masonry sand per quart of latex paint)
surround groups of trees/ shrubs with 3 ft. high fencing strong enough to withstand a 60 lb animal pushing on it or attempting to get under it
apply and reapply deer and big game repellent

Diet and Behavior

Nocturnal and non-hibernating, beavers eat plants; leaves, bark twigs, trees, willow, cottonwood and other deciduous trees. They’ll also eat garden plants if given the chance.

Pairs may mate for life but are not always monogamous. Kits are born between April and June, remaining with their parents for two years. A beaver colony usually consists of a breeding pair and several generations of their kits.

A full grown beaver can grow up to 60 pounds. (Fossil records show that they once reached 300 lbs!) Their lifespan in the wild is between 5 – 10 years.

Spending most of their time in the water, beavers have few predators. When on land, they are most vulnerable. Predators include; man, wolves, coyote, mountain lion, bears, bobcats, and dogs.

The Beaver Butt Thing – Castoreum

Aside from fur, trappers learned of another beaver special quality; castor glands, located near the anus, smell vanilla sweet. Castoreum is secreted with urine to mark territory. One can’t help imagining the very first gland discovery. A mountain man noticed it while taking the animal apart. To verify, he needed a close-and-personal secondary sensory test. Enthusiastic conversations between trappers spread the news and began a new industry.

Castoreum, a thick, syrup-like ooze was used in the perfume industry, starting in the 1800’s, to enhance other scents and increase their longevity.

“The United States, the Food and Drug Administration lists castoreum extract as a generally recognized safe (GRAS) food additive. … While it is mainly used in foods and beverages as part of a substitute vanilla flavor, it is less commonly used as a part of a raspberry or strawberry flavoring.” Wikipedia

Despite Castoreum’s listing with the FDA, it was never a substance in wide use. Anesthetizing and milking beavers was time-consuming and costly.

[Castoreum should not be confused with Castor, as in Castor Oil, which is a plant.]

Beaver Adaptations

continuously growing incisors
an insatiable need to build at the sound of water
tail functions as extra leg while on land
a mouth valve that keeps water out while carrying/floating a tree or branch
ear valves with the same function
back of throat valve – ditto
nostril valves – ditto
nictitating membrane covers eyes underwater acting like goggles
tail slaps on water warn of danger
hind foot has a split toenail used as a comb
fur is waterproof, treated with an oily substance
intestinal bacteria ferment cellulose to digest plant matter — this is why castoreum smells so good!

California Native & Aquatic Keystone Species

The National Geographic Society describes a keystone species as an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether.