Animal Tracks - Beaver Tracks (Castor canadensis)


Lodges are dome-shaped are built in deep water. Lodges are built with wide bases, sometimes up to 20 feet wide. The top can stand ten feet high. Entrances are under water and the beavers swim away from the lodge before surfacing. Dams and lodges are constructed of interwoven branches. The water behind the dam generally is backed up to a depth of four to six feet. Dams can be wide, often five feet or more. The length of the dam depends upon the width of the stream. Beaver ponds provide habitat for various species of fish, and other mammals, such as otters, that feed on the fish. Ospreys and other birds will nest in the dead snag trees that are killed by the flooding caused by the beaver pond. These birds feed on the fish in the pond. Toppled trees are an obvious sign of beaver activity. A groove is gnawed all the way around the trunk in an hourglass shape. The downed trees are stripped of bark. Trees of a diameter approaching three feet can be felled by beavers. Beaver pelts are thick and lustrous, factors which led to extensive trapping of beavers for both their pelts and their meat. The fatty tail, which is reputed to be very good tasting, was considered to be a delicacy. In many areas, beavers had been exterminated by trapping by the 1900s. Trapping regulations were enacted to protect beavers and this drove up the price of beaver pelts, making them unaffordable to most people. The beaver’s preferred habitat is near water. They love aspen, birch, willow, cottonwood, basswood, and poplar trees. The trees are used as building material as well as food. Beavers are vegetarians. They eat cattail shoots, parts of pond lilies and other aquatic vegetation, and trees. They don’t really eat the wood, just the bark. An adult beaver can fell a tree 10 inches in diameter in about six minutes. Beavers stash trees underwater for use during the winter. They will drag a limb down and plant the heavy end in the mud at the bottom of the pond. When the pond is frozen over and it is hard to find food, the beaver can take advantage of this stash. Beaver kits are born in May and June. Litter size is usually about four. The health of the mother beaver influences how many kits are born. If she has had good nutrition and an abundance of food, a larger litter size is possible. The babies are about one pound at birth and are born with a full coat of fur and their eyes open. Kits can swim, but it may take them a month or more to figure out how to hold their breath and swim underwater. When they get tired, they catch a ride on their mother’s back. Beavers mate for life. The older kits may help care for and defend the younger ones. Because beavers are social animals, there can be as many as 18 beavers in one pond. When they are about two years old, beavers go in search of their own territory. They may wander ten miles to find a location to build a new pond. Since beavers live near water, their tracks are often found in mud, which gives good detail to the prints. Beaver tracks show webbing on the hind feet. Hind tracks can easily be six to seven inches long. All feet have five toes. The prints show five toes on the hind feet and four toes on the front feet. The fifth front toe sometimes registers, but not on all surfaces. Front tracks can be two to three inches long. Claw marks show in the tracks. Beavers walk plantigrade, or flat-footed. The large tail sometimes leaves a drag mark in the trail. Beavers can run at six to eight miles per hour. Beavers groom their fur with an oily substance called castoreum which comes from glands. This is the substance that gives the animal's fur its waterproof qualities. Beaver scat is commonly deposited in the water. When it is deposited on land, it is on the edge of the water. Scat appears composed of sawdust and is cylindrical. The segments are 1½ to 2½ inches long. Beavers establish scent posts near their ponds. These are composed of a mound of mud, grass and sticks piled up into a dome-shaped mass. The beaver rubs castoreum on the mound. Some of these mounds can be huge, measuring a foot tall and three feet across. The main predators of beavers are foxes, owls, otters, hawks, alligators, bobcats, coyotes, and lynx. Adult beavers are good fighters and most predators leave them alone. Beavers maintain their dams so that the pond water level stays up. If a dam breaks, the beavers will frantically rush to repair it before all the water rushes away. Beavers don’t make much sound. The young can make sounds that resemble a duck quacking. They also whine and make several other noises. Adults sometimes grunt while working, but are generally silent. One sound beavers are well-known for making is the tail slap. To warn other beavers of danger, the tail will be brought down flat against the water to make a loud slapping sound.


Here are the right front and right hind tracks of a beaver. To the left of the tracks, you can see the drag mark left by the tail. The hind track, which is the larger one, was partially destroyed by the tail drag.


A hind track, facing to the right. Notice that the claws dig into the soil. The toes are long and thick. Webbing between the toes is sometimes visible in the beaver's tracks. A lot depends on the soil conditions though. If the beaver walks through nice fine mud, most of the details of its tracks may be left behind.


The beaver above was exiting the water of the Mad River. Notice that most of the tracks were wiped away by the tail drag mark.


Look closely at this gnawed branch end for the tooth marks left by the beaver.


A beaver's sharp teeth allow it to easily cut through branches such as this. This sign looks different from that of rabbits due to its size, and also distance above the ground. The tooth marks will also help you identify the animal that made the sign. These tooth marks are too big for it to have been a rabbit.


Tree felled by a beaver in Washington state. This is an old sign. Notice how plants have grown up around it and the moss is growing on the log.


The 45 degree angle of this cut can be confused with rabbit feeding sign. However, a closer look will tell you that this branch was way too large to have been cut by a rabbit.


Close-up view of the beaver's tooth marks on the branch.


A scale helps you to tell how big the marks are.


The sand was covered with the tracks of humans and vehicles, but these drag marks were made by a beaver dragging cut branches to the water. Such drag marks are easy to follow in sand. You can follow them backward to find where the beaver was working.


The outer two trails show where a beaver came out of the water and dragged its tail as it made its way up the slope. The trails in the middle were made as the beaver went back into the water, dragging branches of willow with it.


A nice clear beaver trail coming out of the river. Notice how heavily the tail drags in this trail. The tracks are barely discernable at the edges of the tail drag mark.


Another area where the beaver dragged cut branches into the water repeatedly.


A beaver's exit trail from the water.


Beaver habitat on the Mad River, near Arcata, CA. The beavers do not build dams here. This river experiences a tidal influx of water and its level raises and lowers each day as the tide comes in and out. The beavers live here, but do not alter the river's flow with any structures. A family of five river otters was also seen at this same location.


Rounded edges and soft contours outline what is left of a beaver track.


Two deep beaver tracks in the center of this trail are partially visible after the tail was dragged over them.


The red arrow in this photo indicates the direction the beaver was traveling when it made this trail.


The large hole to the middle left was made by my foot as I walked into the center of this beaver sign. Nice drag marks were made by the willow branches the beaver was harvesting.


The cut branch ends where the beaver had been working.


The best beaver tracks I found that day. These were the only ones not completely destroyed by tail drag.


Beaver tracks partially obscured by the dragging tail. Photo taken October 2007 at Colusa-Sacramento River State Recreation Area. Thanks to Jean Franklin for the use of the photos in this section!

Beaver tracks and beaver slide areas on river bank. Photo taken October 2007 at Colusa-Sacramento River State Recreation Area.

Beaver slides or trails. These are places where they regularly drag branches toward the water.

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	Beaver Tracks and Signs
	*Castor canadensis*



	4.75-7 in. L x 3.25-5.25 in. W	2.5-3.75 in L x 2.25-3.5 in W

Beaver Tracks

	The beaver is a familiar animal that inhabits most of the U. S. They are found just about everywhere except southern California, most of Florida and Nevada, and parts of Alaska. However, there are some isolated populations of beaver reported to be in Riverside County, California, in Temecula Creek. This is one of the largest rodents. Beavers weigh 45 to 60 pounds. Historically, beavers weighing over a hundred pounds were common.
Beavers are well-known as the builders of dams and lodges. Their long incisor teeth help them to cut down trees by gnawing their way all the way around the tree trunk. Beaver dams back up the water into ponds which change the habitat of that area. The ponds create marshy areas which allow certain trees to grow. These in turn support different species of wildlife that can live in a riparian environment. Over time, a beaver pond will become a meadow, then shrubs will begin to grow. The shrubs will provide shade that allows tree seedlings to get started. Once these trees grow tall enough, they shade out the shrubs. The trees will eventually grow into a mature forest. This cycle is called forest succession and many factors play a part, but the beaver helps to begin the process by building its dams.

Beavers do not always build dams. They can live on a river and use burrows and eat vegetation without building any structures. Look for their tracks and signs along sandy river banks. You might find areas where limbs have been dragged into the water. Beavers will come ashore and gnaw off branches then take these back to eat later. Look along the shores for branches showing the tooth marks of these large rodents. Beaver tracks are often obliterated by the tail as it drags over them. You may find partial tracks or tracks that show a clear mark as if something heavy was dragged over them. Some of the photos below show this characteristic.

	A beaver eating.
The front foot of a beaver is at right. The green material is from its enclosure. This animal was part of a rehabber's presentation.


The hind foot of a beaver, showing the webbing between the toes. This greatly helps them swim! Those are big feet too!