Pinedale Online!

Visitor's Guide to Pinedale, Wyoming

Home | Calendar of Events | Photo Gallery | Local Businesses |

Pinedale Online > News > May 2006 > Beaver Country

Typical Beaver Pond. Photo by Pinedale Online.
Typical Beaver Pond
A small beaver pond on South Cottonwood Creek in the Wyoming Range, with Triple Peak in the background. The beaver lodge can be seen on the opposite bank.

Morning Beaver. Photo by Pinedale Online.
Morning Beaver
Beaver almost always work at night, so are rarely seen. This beaver was seen just after sunrise at New Fork Lake this spring, before it retired to the lodge for the day.

Renovated Beaver Lodge. Photo by Pinedale Online.
Renovated Beaver Lodge
This large beaver lodge on New Fork Lake has an old section, characterized by more mud, and a new section primarily of logs. The new section is over 5 feet tall. Note the person standing in front of the lodge.

Large Aspen. Photo by Pinedale Online.
Large Aspen
This aspen tree on Stepp Creek, a tributary of LaBarge Creek, was felled by a beaver many years ago. The trunk measures 2 feet in diameter. Beaver have been known to bring down trees as large as 3.5 feet in diameter.
Beaver Country
by Clint Gilchrist
May 29, 2006

From 1824 to 1840, the Green River Valley in western Wyoming was the geographic and operational center of the Rocky Mountain Fur Trade. It was the earliest "economic boom" industry in our valley, creating fortunes for many, just as oil and gas is doing here now.

The underfur of the beaver makes the best quality felt. For several hundred years, beaver were trapped throughout the world. During that time, beaver were trapped out of most of the world and even North America. By the 1800s, the Rocky Mountains were the last untapped source of beaver, a gold-mine in its own way.

In 1824, Jed Smith, along with ten other men, came over South Pass and found a "Mother Load" of beaver in the tributaries of the Green River of western Wyoming. This started the Rocky Mountain Fur Trade and created the now-mythical Rendezvous and the Mountain Man.

The Green River Valley was likely trapped heavily in the late 1820s, leaving few beaver to be found in the 1830s. However, because of its central location, the Green River Valley became the preferred location of the summer Rendezvous, the gathering of the trappers, fur traders, Native Americans and trade good suppliers. Half of the 16 rendezvous were held in the Green River Valley, and 6 of the last 8 were held on Horse Creek near Daniel. By 1840, silk hats had become the fashion and beaver trapping was no longer profitable on a large scale, bringing an end to the booming Rocky Mountain fur trade era.

One hundred and sixty six years later, the Upper Green River Valley is still beaver country. Beaver are certainly not as numerous today, but signs of their presence can be found on almost any stream or lake in the area. Unless you stop and look close, it is easy to miss the details of the work of nature’s engineer. Over the past month, we have visited several beaver sites to observe their handiwork in areas not far from Pinedale. None were hard to find, all accessible by roads. By being observant, it is not hard to recognize their activity, and it is another fun thing to do while out exploring this beautiful country.

The beaver is a rodent, cousin to the rat, but well adapted to the water. They are very clumsy on ground. They eat any water vegetation when available, but their preferred food is willow or poplar tree bark and leaves. Their favorite is aspen tree bark and will often go to great lengths to get it.

Beaver habitat is any body of water deep enough to swim in and not freeze solid in the winter. There must also be willow or poplar trees within a few hundred yards, preferable on the banks.

They build their homes, or "lodges", of segments of logs and branches packed with mud. They build an underwater entrance to allow them to enter and leave their lodge safe from natural predators such as bear, wolf and cougars.

In small mountain streams with abundant food, but not large enough to swim, beaver will build dams of sticks and mud to back up the stream flow to create ponds which provide their own habitat and protection.

On large streams and lakes they do not need to build dams and only build lodges on the bank. A beaver dam was found on Coal Creek in the Wyoming Range in the 1950s which was 18-feet tall and created a pond with a perimeter of one mile.

Beavers enlarge their dams when silt starts to fill up the pond or to expand the shoreline as food near the pond is consumed and they need to travel further to obtain it.

Beaver are prolific builders. Ten beaver released on Little Cottonwood Creek in 1949 create 55 dams within 1 year. Although fish, birds and other wildlife thrive in beaver ponds, theese animals are irrelevant to the beaver. Also, beaver do not eat fish as many believe.

A typical adult beaver weighs 40-60 lbs, is 2.5 to 3 feet long, and has a foot-long tail. Beaver have been recorded to weigh as much as 110 pounds. They mate for life and generally do not build a home until they find a mate. They typically have one litter a year with an average of four young, or "kits", which will stay with their parents until they are two years old. At that time, they are kicked out by their parents and must venture out on their own to find a mate and a new home. Beavers have been found roaming as much as 160 miles looking for a mate and a new home.

Beaver typically work almost exclusively at night, so are rarely seen. The best oportunity to see a beaver in day light is in the months of April and May when two-year olds, widowed males, or even families are out looking for a new home.

Beaver will generally avoid humans and are not dangerous. However, if you venture too near their work grounds or lodge during the night, one of the adults will generally swim over and check out the intruder by swimming back and forth sniffing the air and listening. If they determine there is a threat, they raise their tail and slap it on the water as a warning. This sounds a lot like a gun shot and is quite startling and very effective if you are near. Beaver do not have very good far vision, but can hear and smell much better then humans.

Photos by Clint Gilchrist and Dawn Ballou, Pinedale Online!

Beaver Stump. Photo by Pinedale Online.
Beaver Stump
To gnaw down a tree, beaver sit on their butt, hold the tree with their hands, and turn their head to the side to chew. This 3.5 foot stump on Camp Creek in the Wyoming Range suggests a very large beaver at work. Fresh chips and green leaves on the tree offer proof the tree was not chewed during winter. This had to be a big beaver to reach this high!

Washed Out Dam. Photo by Pinedale Online.
Washed Out Dam
Beaver dams sometimes break during high waters of spring flooding, and are then repaired during the summer. Some dams wash out every year and are rebuilt each summer.

Bare Creek Dams. Photo by Pinedale Online.
Bare Creek Dams
A series of three smaller beaver dams are easier for a beaver to build than one big one. Beaver live in just one pond, and use the others for easier traveling.

Human Conflict. Photo by Pinedale Online.
Human Conflict
Here, a beaver has built a dam using South Cottonwood Road to anchor one side. During high spring flows the dammed up water has almost breached the top of the road. This sort of beaver activity can wash out roads if allowed to go too far.

Distructive Beaver. Photo by Pinedale Online.
Distructive Beaver
A dozen 4-8 inch diameter freshly cut aspen trees were found on this beach only a couple days after ice went off New Fork Lake this spring.

Good Swimmers. Photo by Pinedale Online.
Good Swimmers
Beaver are well adapted to swimming. Their nose and ears are out of the water to scan for danger and food. Beaver can hold their breath underwater for up to 15 minutes.

No More Trees. Photo by Pinedale Online.
No More Trees
This used to be a grove of aspen trees near New Fork Lake. Beaver dug this groove in the bank and made a well-worn path leading to an area they worked for years to gather food and logs for building their lodge. Now, only short brush grow here. New aspen are cut when only a few feet tall and won't regenerate as long as beaver live here.

Tree Tops. Photo by Pinedale Online.
Tree Tops
Large trees like this 8-inch base diameter aspen are often chewed down by beaver just so they can get to the smaller branches at the top. The rest of this tree was not used.

Beaver Handiwork. Photo by Pinedale Online.
Beaver Handiwork
These aspen trees were chewed down by beaver and all branches removed and carried away for food. The remaining tree segments will likely not be used by the beaver and will be left to decay on the lakeshore.

Hungry Beaver. Photo by Pinedale Online.
Hungry Beaver
Beaver prefer to eat the bark of younger trees for their food, and usually drag the log segments to a safe feeding area. This large tree, eaten where it fell, suggests hungry beavers.

Beaver Chew Marks. Photo by Pinedale Online.
Beaver Chew Marks
Aspen bark and leaves are the prefered food of beavers. They do not eat the woody part of the tree, but do use it for building their lodges and dams.

Unfinished Business. Photo by Pinedale Online.
Unfinished Business
Beaver often do not finish chewing on a tree in one sitting and sometimes never return to finish bringing it down.

Wearing Down Teeth. Photo by Pinedale Online.
Wearing Down Teeth
A beaver's teeth never stop growing and they must chew on wood regularly to wear them down. That may have been the purpose for chewing this large log.

Morning Meal. Photo by Pinedale Online.
Morning Meal
Here, a beaver eats bark near his lodge just before sun rise after a long night of working on New Fork Lake. Beaver usually take their food to a safe feeding area.

Beaver Wood Chips. Photo by Pinedale Online.
Beaver Wood Chips
Beaver have very powerful jaws and sharp teeth, allowing them to make quick work of falling trees. Typical wood chips are an inch wide and 2-6 inches long. A large adult beaver can cut a 1- inch tree branch with one powerful bite.

One piece at a time. Photo by Pinedale Online.
One piece at a time
At one time, a tree lay on the ground here, felled by beaver. Wood chip piles spaced about 5 feet apart are what's left of the segment lengths the beaver chewed the tree into before carrying them off to his lodge for food.

Timber!!. Photo by Pinedale Online.
This random fall pattern of cut trees demonstrate beaver do not try to control the directions trees fall. There are no trees across the beaver's work and drag trail, which is likely because those tree pieces were removed.

Green River Lodge. Photo by Pinedale Online.
Green River Lodge
Beaver that live along larger rivers do not need to build dams to back up water. Their lodges are built along the river's bank. This lodge is on the Green River near Green River Lakes.

Transformed Canyon. Photo by Pinedale Online.
Transformed Canyon
Little Fall Creek was once a narrow ravine, but beaver activity over many years has filled it in, flattening the valley bottom.

Late Stage Beaver Pond. Photo by Pinedale Online.
Late Stage Beaver Pond
After many years of use, a beaver's pond will eventually silt in. The end result of a sucessfull beaver pond is a flat meadow or willow grove. This pond on Little Fall Creek is heavily silted in and will likely be abandoned soon by the beavers living here.

Old Beaver Cuts. Photo by Pinedale Online.
Old Beaver Cuts
These large aspen trees were chewed and felled many years ago, but still show the distinct marks of the beaver's activity. A fire later swept through this area, charring the fallen trees.

Long Trail. Photo by Pinedale Online.
Long Trail
Beaver are most vulnerable to predators while on land, but will risk travel, especially for aspen. This stand of aspen on LaBarge Creek is 200 feet up a steep embankment.

Work Near a Road. Photo by Pinedale Online.
Work Near a Road
Here, beaver sign shows they climbed 200-300 feet up a very steep embankment from LaBarge Creek in the distance, then have no problem working next to LaBarge Creek road and dragging trees and branches back down to their lodge on the stream.

Double Cut. Photo by Pinedale Online.
Double Cut
Here, a beaver chewed the upper cut first. This aspen tree started to fall, but then got hung up in other trees and did not fall to the ground. The beaver then began another chew spot lower on the tree.

Drained Beaver Pond. Photo by Pinedale Online.
Drained Beaver Pond
Spring floods on LaBarge Creek breached a beaver dam this spring, allowing the pond to partially drain and leaving mud flats.

Chew Cut Willows. Photo by Pinedale Online.
Chew Cut Willows
Aspen bark is the preferred food of beavers, but willow bark is well liked and often more available. This bush shows fresh and old beaver chews and harvest.

Beaver Trail. Photo by Pinedale Online.
Beaver Trail
At first glance, this might appear to be a big game trail. Here, beaver have made a well-worn path to their work area where they are cutting down trees and gathering branches for food. Because walking on land is difficult for beavers, they tend to reuse the same travel paths. Dragging log segments to the water to take back to their lodge also wears the trail on the land down to the water's edge.
Pinedale Online > News > May 2006 > Beaver Country

Pinedale Online!
Pinedale Online! PO Box 2250, Pinedale, WY 82941
Phone: (307) 360-7689 or (307) 276-5699, Fax: (307) 276-5414

Office Outlet in Pinedale, 43 S. Sublette

Copyright © 2006 Pinedale Online. All rights reserved.
Pictures and content cannot be used in whole or part without permission.