Science Corner - North American Beaver (at Conaway Ranch!)

Kristie Ehrhardt • June 5, 2025


The North American Beaver also commonly called American Beaver, Canadian Beaver or just beaver is the largest member of the rodent family in the United States. The word rodent means “to gnaw” and rodents are characterized by a pair of continuously growing upper and lower incisors. Beavers must constantly gnaw on trees to keep their teeth from getting too long. About 40% of all known mammal species are rodents and are native all over the world with the exception of Antarctica.

 

It is believed that beavers are from ten to twelve million years old and fossils were first discovered in Germany. It is thought that these beavers used the Bering Strait to reach North America about seven million years ago. Today there are two distinct species of beaver; the American Beaver (Castor canadensis) and the Eurasian Beaver (C. fiber). The American Beaver is the species found in the United States and the rest of North America.

 

American Beavers (beavers) are semi-aquatic spending at least part of their day in water. Their tails are large, flat and paddle-shaped and when combined with their webbed hind feet, beavers are excellent swimmers. Beavers also use their flat tails to slap the water to signal danger to other nearby beavers, to store fat and to help them balance when toting loads of heavy logs and branches. Beavers' front feet are smaller than their rear feet and have claws rather than being webbed. Their front feet are extremely dexterous and give them the ability to grasp and rotate pencil-thin stems, peel off bark, dig and put food such as small leaves in their mouths. Another adaptation of semiaquatic life includes a nictitating membrane which covers and protects the eyes so they can remain open under the water allowing them to see and ears and nostrils that are able to seal shut while under water. Despite their large incisors, beavers are able to close their mouths over their teeth. Beavers range from about 25 pounds to over 70 pounds but the average is around 50. They are about 30 to 35 inches from nose to rump with tails that range from eight to nearly 14 inches long. Beavers sport a rich, dark chocolate-brown double coat which includes long, coarse outer hairs and short, fine and dense inner hairs. This coat helps keep the beaver’s body dry and insulates it from cold and hot temperatures. Beavers have two sets of scent glands. One set produces an oily substance called castoreum (which is where the beaver’s Genus, Castor, comes from and is used to waterproof their coats. The other set of scent glands produces waxy chemicals that help identify one beaver to another. Beavers also have a thick layer of fat just under their skin that also helps keep them warm while in cold, sometimes icy water. Beaver fur was so sought after at one point in time that they were nearly driven to extinction.

 

Beavers are primarily nocturnal but can also be active during the day and spend their time going to and from water collecting bark, leaves, roots and wetland plants to eat. They excel at swimming and can remain underwater for up to 15 minutes. Which is advantageous because they spend an awful lot of their time designing and building their homes and water control structures. Beavers build their dwelling or lodges using rocks, sticks and mud in waterways and other bodies of water. Their lodges may be juxtaposed to land or surrounded entirely by water. The inside of the lodge is covered with mud which dries to the consistency of cement keeping the lodge warm and dry during the cold, wet months. A breathing hole is left open at the top of the lodge and entrances are underwater. Lodges have multiple chambers and different elevations to keep them either moist for feeding or warm and dry for sleeping. Beavers also build dams in order to back up water and form deep ponds to allow for the beaver to escape predation from coyotes, wolves, mountain lions and other top predators. Dams are built using longer branches, vegetation and mud. If tree branches and vegetation are not available beavers will use rocks to build their dams. Branches, sticks, twigs and vegetation are cut using their incisors and carried and put in place using their front feet. Dam building not only provides a refuge for the beavers but it also creates and enhances habitat for other amphibians, fish and waterfowl. Beaver dams also help reduce soil erosion and may lessen the impacts of flooding.

 

Beavers are monogamous and mate at about three years of age. Only one litter of one to four kits is born a season and usually remain with their parents inside the warm, safe lodge for up to two years.

 

Beaver Facts : 

  • At one point beaver fur was so valuable, primarily for hats and shirts that the species was on the brink of extinction. Today it is estimated that there are about 10-15 million American Beaver occurring throughout its range in North America and are considered invasive species in some places!
  • Very old beavers can weigh over 100 pounds (about the weight of a king size mattress)!
  • It’s believed that the sound of running water is what urges beavers to build or repair their dams. The largest beaver dam was discovered by satellite imagery in 2007 near Alberta, Canada. It was nearly a half a mile long and two times wider than Hoover Dam!
  • Beavers are considered “keystone species” because their activities provide increased biodiversity by forming or enlarging wetlands and surrounding riparian habitats - they are unique in that they can change the landscape!

 

Be sure to check out Tuleyome’s Youtube channel for a very close up (!) view of beavers and other wildlife friends at play at our partner in conservation Conaway Ranch!


-Kristie Ehrhardt (kehrhardt@tuleyome.org)

Tuleyome Land Conservation Program Manager

RECENT ARTICLES

By Bryan Pride January 20, 2026
Last year tested us. We watched as the administration attempted to auction off millions of acres of public lands, an unprecedented attack on places we’ve fought to protect for decades. We saw rollbacks of critical environmental protections and threats to lands that belong to all of us. But we also showed up. Together, as a community, we rallied, we organized, and we pushed back against some of the most aggressive land sell-offs ever proposed. And we won some of those fights. In December, just before Congress recessed, Senator Padilla introduced the Protecting Unique and Beautiful Landscapes by Investing in California (PUBLIC) Lands Act , a beacon of what’s possible when we refuse to give up. This isn’t just another bill. It’s a statement that California is refusing to let our public lands become bargaining chips. The PUBLIC Lands Act would protect over 1.7 million acres of California public lands throughout northwest California, the Central Coast and Los Angeles County. That protection includes 550,000 acres of new wilderness and nearly 700 miles of wild and scenic rivers. It includes provisions for forest restoration and fire resilience on another 871,000 acres, work that is desperately needed. This package pulls together three essential bills: Congressman Huffman's Northwest California Wilderness, Recreation and Working Forest Act , which protects 484,733 acres and 479.8 miles of rivers, old-growth forest, salmon streams and wild places that define the North Coast. Representative Carbajal’s Central Coast Heritage Protection Act secures 385,842 acres including critical habitat in Los Padres National Forest, home to California Condors and threatened watersheds. Representative Judy Chu’s San Gabriel Mountains Foothills and Rivers Protection Act that protects 35,335 acres, expanding access to nature for millions of Angelenos who live in communities with some of the lowest park access in the country despite having mountains right in their backyard. The PUBLIC Lands Act matters because it’s happening now when our public lands face their greatest threats. Our champions in Congress aren’t waiting for a better political moment, they’re fighting for these places when the fight matters most. We will be tracking this bill closely and keeping you updated as it moves through Congress. In the meantime, call your representatives and thank Senator Padilla , Representative Huffman , Representative Carabajal and Representative Chu for introducing this legislation. Let them know you support it. Our voices help move good legislation through Congress, especially when the opposition is loud. If 2025 taught us anything, it's that defending our public lands isn’t a one-time battle. It’s the work we do together, every single day. Bryan Pride Tuleyome Policy Director
By Kristie Ehrhardt January 20, 2026
It’s true! Tuleyome’s Adventures and Engagement Director Nate Lillge has assembled an incredible guide to the trails located throughout the southern portion of our newly expanded favorite monument. As you may know, the monument is jointly managed by both the Bureau of Land Management (under the United States Department of Interior) and the United States Forest Service (under the United States Department of Agriculture). The two agencies collectively manage and maintain 344,476 acres of natural wildlands in the Inner Coastal Range available for the public to appreciate and explore. That’s where Tuleyome comes in, we want to help you traverse and investigate those acres. Tuleyome’s trail guide not only provides a map of the southern portion of the monument with the trailhead names and locations, but it also shows names of the various trails that can be accessed by those trailheads along with the difficulty rating. It also contains a QR code that will take you to detailed information for each trail, including driving directions, trail maps and hike descriptions. If you’d rather go with a group, Tuleyome can help there too. Check out the Upcoming Events tab on our website to register for one or more of our organized hikes. So, if your New Year’s Resolution was to get out on more hikes in 2026, Tuleyome’s got you covered! Check out the Trail Guide here or look for our booth at one of the many community events that we participate in and pick up a printed copy. And don’t forget about our Youth Boot Bank program if your little hiker needs to borrow some boots; just come see Tuleyome’s Education Associate, Geoff Benn, during Boot Bank office hours, which are also listed under the events tab, and we’ll get your little ones outfitted for the trails too. Happy Hiking!!  -Kristie Ehrhardt ( kehrhardt@tuleyome.org ) Tuleyome Land Conservation Program Manager
By Kristie Ehrhardt January 20, 2026
Stretching from the Bering Straight off the coast of Alaska south to majestic Patagonia, the Pacific Flyway is one of the paramount migratory pathways in the entire world. Hundreds of species ranging from tiny hummingbirds, songbirds like sparrows and warblers, shorebirds like avocets, sandpipers and whimbrels, waterfowl including many species of ducks and geese to great Bald Eagles combine to equal the billions of birds that use the Pacific Flyway each migration season. With California's mild winters, available wetlands and flooded rice fields, and oodles of food, it’s not hard to see why waterfowl species like the striking white and black Snow Goose spend their winters here. As many as a million and a half Snow Geese will be using the Pacific Flyway and tens of thousands of them will remain here, in our region, for the winter. The City of Chico and surrounding communities come together to celebrate “this magnificent spectacle of nature with the Snow Goose Festival of the Pacific Flyway.” By connecting and showcasing artists, authors, educators, guides and volunteers the festival aims to excite and unite the community by increasing appreciation, awareness, conservation and understanding of the resident and visiting wildlife and their habitats in the Northern Sacramento Valley. The three day festival features art and an auction, a banquet, field trips, family activities and exhibits and workshops! Snow Geese (Anser caerulescens) breed in Greenland, Canada, Alaska and the northeastern tip of Siberia and winter in the warmer regions of southwestern British Columbia, south through the United States and Mexico. There are two color morphs, white which are called “snows” (shocking, I know) and the dark morphs which are called “blues”. Snows are all white with black wingtips while blues have dark bluish-gray plumage and a white head, neck and tip of the tail. Both color morphs have orangy-red legs and feet and a pink bill with black edges that makes it look like they are grinning. Sometimes minerals in the soil or water where they’re feeding can stain their white heads making them look orange. Snow Geese are vocal. Very vocal. Some may say they are extremely vocal and they can often be heard from more than a mile away. Frequently Snow Geese and Greater White-fronted Geese travel together as they are very similar in size and needs. Combined flocks of them can often be heard on winter days and nights as they fly high overhead to their feeding grounds. If you’re looking for a fun way to Enjoy Outdoors and learn more about the Pacific Flyway, Snow Geese and their fellow travelers, venture on up to Chico during the weekend of January 22-25, 2026. They’d love to see you at one of the many events! Please visit the website ( https://snowgoosefestival.org/ ) for a list of activities, to register and for more information. Snow Goose Fun Facts! When Snow Geese are resting or feeding, lookouts keep an eye to the sky watching for threats such as Bald Eagles or other predators which prey on old or injured geese. The lookout will vocalize and the entire flock may spontaneously take flight which is pretty stunning to watch. Snow Goose eggshells stain easily which makes aging the eggs easy, the older eggs will appear dirtier while the more recently laid eggs remain creamy white. Snow Geese populations dropped so low in the early 1900’s that hunting was no longer allowed in the eastern states. From the 1970’s and on, the population has boomed so much that some of their tundra nesting grounds are being impacted by their numbers. Once females arrive at their breeding grounds they may spend up to 20 hours a day foraging but consume nearly nothing once they begin incubating eggs. Snow Goose digestion is remarkably quick, requiring only about an hour or two to go from gullet to ground. Snow Geese make epic journeys by wing but they are not lazy on foot either. Within the first month after hatching, goslings may walk about 50 miles with their parents. When waterfowl molt they lose their ability to fly but a molting Snow Goose can outrun many predators. The oldest known Snow Goose was over 30 years old! Word Play. A group of geese on the ground or water is called a gaggle . That same collection of geese but now in the air are called a skein , a wedge or a team . Hunters use the term “ grind ” for an assemblage of geese while culinary artists use the same term to mean goose meat . BUT, if you simply call them a flock of geese, everyone will know what you’re talkin' about! -Kristie Ehrhardt ( kehrhardt@tuleyome.org ) Tuleyome Land Conservation Program Manager