Beavers are a keystone species. They create wetlands that support a rich diversity of life. Many animals and insects benefit from the efforts of beavers, including salmon, frogs, turtles, birds, otter, deer, elk, and dragonflies.
Oregon is the beaver state. It is the only state with a two-sided flag, and one side is dedicated to the beaver.
Beaver are busy! The largest beaver-built dam was discovered through satellite imagery to be 2800 feet long. That is twice the length of the Hoover Dam. Do not underestimate the building drive of beavers. They have a strong work ethic and work together toward shared goals: safety, community, and gathering food.
Humans also benefit. Beaver dams improve water quality, slow climate change by trapping and storing carbon, and help slow down or stop wildfires. After wildfires, beaver zones remain green and offer protection for both wild and domestic animals.
What makes a beaver?
They are usually reddish brown to almost black in color. Adults often weight 50-65 pounds and are about 4 feet long including the tail. They have valves in their ears and nose that close when they go underwater, and see-through protective eyelids that act like goggles. They paddle with their webbed hind feet. They can hold their breath up to 15 minutes and swim faster than olympic swimmers.
No other animal has anything like a beaver tail. It is about 12 inches long, with small scales and no hair. It helps steer during swimming. It acts as a balance to allow standing up and waddling on hind feet (yes the beaver can walk upright).
Fat is stored in the tail, which can lose half of its thickness by the end of winter. The tail also regulates body temperature. During hot summers, when a beaver dives into cool water, the tail helps shed excess body heat. The paddle-shaped tail is used to slap the water to make loud warning sounds.
From fur to hats
Beaver fur has about 100,000 hairs per square inch, while a human has only about 1,000 hairs for the same space. Beaver felt, made from their downy inner fur, performs best. It does not flop, droop, or fail in the rain. Such toughness and warmth made everyone want a beaver hat. The top hat, bicorn, pilgrim, and the three musketeer plumed chapeaux were all made from beaver fur.
To keep up with hat production, the beavers of Europe were wiped out first. Then Europeans came to North America to trap more beavers. After many years of this, humans significantly reduced their numbers from many millions to the low thousands. They are bouncing back now. It’s good for them, and us, that beaver felt hats went out of style.
Scientists note that these animals are natural hydraulic engineers. They instinctively know exactly how to design ponds for their advantage. They work all night. You can hear them talking, chewing trees and shrubs, and swimming back and forth between the job site and the materials.
Productive nature
Some favorite materials for building dams and lodges are willows, mud and aspen branches. Beaver houses are called lodges and they are the same as dams, except they live inside them. When making a lodge, they usually start piling peeled sticks along the bank of a stream.
They strategically fall trees they want to use – dragging the small ones over land, and floating larger logs along waterways toward the building site. They start by anchoring logs and branches on the sides of the stream or pond. They quickly weave them together to build a teepee-shaped structure. Eventually, a lodge can be 40 feet across and 10 feet high.
Piles of logs and branches won’t stop all the water flow because of cracks, so the beavers dive down to scoop up armloads of mud and use their paws to fill in the gaps to make the dam a firm water block.
They caulk their lodge the same way each fall to keep out the cold. Only a small vent at the top remains open. Once frozen, a lodge is strong enough that a bear can’t break into it.
When making the lodge interior, they dive to lower levels and chew and dig upward into the solid stick structure to create multiple underwater entries and exits. Their lodge is clean, dry, and safe. They make beds using reeds and grass. They have a sleeping area and a resting area. They do not soil inside their house, they leave all droppings outside in the water.
Cold weather strategies
Beavers don’t hibernate. When they live in extremely cold places like northern Canada, their lodge is covered over by ice from November to March. They have no exits to get out above the ice, only to swim around in the water below and breath air from a thin space between the water and ice.
It takes planning to survive.
At the first sign of frost, they begin to drag green branches underwater, and near their lodge to build a large food storage. This functions as the pantry for long months under ice. Once it warms up, they bump through the thin ice with their heads and forage for fresh food.
Balancing the ecosystem
Until recently, we thought large populations of beavers destroyed vegetation and forests. Long term studies have shown the opposite is true. The U.S. Forest Service is now working to establish healthy beaver populations to benefit humans, animals, and the planet.
If you or someone you know is needing help coexisting with beavers, look into a device called the beaver deceiver. It has proven to be effective in managing unwanted flooding while creating a harmonious relationship between humans and beavers.
https://www.beaversww.org is a great resource
Beaver photos taken by the Oregon zoo.