It is incredible that such a small body could contain such a remarkably vicious nature as that of the weasel. Most animals kills for food, but the long saber-sharp teeth of the weasel kill wantonly and apparently just for the sake of killing. They first suck the warm blood from the base of the skull or neck of their victim and then eat portions of its meat and bones. They are quick and intelligent and can subdue animals several times their size. They are quite common throughout the Park up to timberline, and are so curious and unafraid that once seen, they may be attracted by making various squeaks and sounds.
SHORT-TAILED WEASEL (Mustela streatori lepta)
A very small weasel differing from the long-tailed weasel chiefly in size. Total length 9½ inches. Rare in the Park.
THE PLANT EATERS (RODENTS)
BEAVER (Castor canadensis concisor)
Compact, heavyset, water mammal with brown fur and a broad, horizontally-flattened, scaly tail. Large, webbed hind feet. Total length about 3½ feet. Average weight about 40 pounds. When swimming, only the top half of the head, shoulders, and part of the back appear above water. For positive identification, watch for the broad, black tail which may slap the water, or “flip up” when it dives.
This largest of North American rodents is very abundant and widely distributed in many of the mountain streams. To locate their dams, look for small pools or lakes in streams of heavily wooded sections. If new, the dams will be a mass of twigs and saplings carefully interlaced and sealed with mud; if old, the dams will be overgrown with grasses and small shrubs, but will still maintain the general shape and contour of a beaver dam. These dams will easily support the weight of a man. In the pond area or on the dam, a conical mass of mud and twigs, (the beaver lodge) some three to five feet high may be found, which contains the home of the beavers using that pond. Each lodge has an underwater entrance which is constantly in use, winter and summer. While beavers work mostly at night, it has been a regular practice in the Park to observe them swimming in their ponds just before nightfall. The Mill Creek, Hidden Valley, and Colorado River Valley areas have been especially good locations for sight of beaver. If aspen, which is both the beaver’s food and construction material, have all been removed for a distance of five or six hundred feet from the pond, then probably the beavers have moved out and gone up or down stream to build a new pond. Muskrats may then occupy the entire pond.
MUSKRAT (Ondatra zibethica osoyoosensis)
This water mammal might well be a miniature beaver to the casual observer, with the one distinguishing feature of having a long, scaly tail flattened in the vertical plane instead of the beaver’s broad, flat tail. Length not more than 2 feet. When swimming, only a small portion of the top of the animal shows above water, along with a thin edge of the tail, which is used with a sculling and rudder effect.
Muskrat are common in the Park, often living in beaver-made ponds. They are therefore often confused with beaver by the uninitiated, but if attention is given to the size and tail characteristics, there will be no identification difficulty. The muskrat or “rats,” as they are often called, build dens in the banks of the ponds and more rarely in this region, small grass and mud lodges. Their principal foods are rushes, grass, and water plants. In ponds containing active muskrat these plants are often found cut and floating near the banks.