One of the most characteristic marks of the woodrat’s home is a strong, musky odor. This is not an indication of uncleanliness. The animal is most fastidious in its toilette but has this body odor in large measure. A study skin will retain a strong trace of it for many years. Whether it functions for an identification to others of the species is not known, but it could well serve this purpose.
Although classed as a nocturnal animal, the bushy-tailed woodrat is often active throughout the daylight hours. They are not gregarious creatures; yet, since suitable nesting sites may not be found in some areas, other more favored localities often will harbor considerable numbers of the animals. Overhanging ledges may shelter the piles of litter denoting a nest every few feet. In such cases, a well-worn trail will lead from one to the other. This is not an indication that a colony lives there in peace and harmony. These rats are truculent creatures among themselves, and if a stranger should venture into a nest mound, he is evicted with many indignant squeaks and a fearsome snapping of teeth. The interloper seems to know he is out of order and usually leaves the nest at once without more than a token show of resistance. In neutral territory such as a cabin, however, several woodrats may share the area quite peacefully, but to the great annoyance of the human occupant.
The variety of sounds produced by such a group is quite amazing. Added to the usual high-pitched squeaks and patter of running feet are the mysterious rustlings of paper and other objects being dragged about. A peculiar thumping sound indicates a gait which I have never seen but often heard at night. It must be somewhat like the leaping flight of a kangaroo rat, at least it indicates a swift succession of leaps across a flat surface such as a floor or roof. Perhaps the broad surface presented by the flat of the bushy tail is of assistance in this maneuver. Then, like most rodents, the woodrat will thump with its hind legs as an alarm signal. This is perhaps the most noticeable sound of all, for it marks the instant cessation of all activity for every member of its kind within hearing distance. The “ear-splitting silence” that follows this signal literally presses in on one in the darkness.
Muskrat
Ondatra zibethicus (French Canadian word from the Iroquois and Huron Indian word for muskrat. Latin: the odorous substance of the civet alluding to the musk secreted by the muskrat)
Range: Virtually all of North America north of the Mexican border. Muskrats are found from near sea level to as high as 10,000 feet above it.
Habitat: This large rodent can exist only near a permanent water supply which is deep enough to shelter it from its enemies. This may be a lake, a marsh, or a running stream.
Description: A large aquatic rodent whose long, flat tail undulates from side to side when it swims. Total length 18 to 25 inches. Tail 8 to 11 inches. Weight 2 to 4 pounds. The thick, dark brown fur of the upper body is overlaid with brown to black guard hairs. The legs are short but powerful. The front feet are small, but the hind feet are relatively large and partially webbed, with stiff hairs on the edges of the webs and along the sides of the toes. The long, black tail is flattened vertically. It is so scantily haired that it may be said to be naked, but is covered with small scales up to 2 millimeters in diameter. The head is quite similar to that of a vole. The ears are so short as to barely protrude through the fur, and the eyes are small. Average number of young thought to be six per litter. Several litters may be born each year.
The presence of muskrats in a shallow lake or marsh is not difficult to detect. This is their chosen habitat, and here in water about 1½ feet deep, they build their characteristic mounds of rushes and cat-tails. Here they may also be seen on quiet days swimming about and carrying on their normal activities. In much of the Southwest, however, such favorite habitats are few and far between and the muskrats must take their choice, if there be one, between the few permanent streams and irrigation canals. In these altered circumstances they react quite differently; they may often be present in considerable numbers without anyone being the wiser. The change in habits required by this different environment illustrates the great adaptability exhibited by many of our most common mammal species.
The most important requirement of a muskrat is a permanent body of water of a depth sufficient for it to dive into and escape from its enemies. Given this, it will at once set about constructing a home. In a lake or marsh, there is little or no current. In sheltered bays, where wave action is slight, the bottom often will be muddy. In the shallow water along the shore, water plants such as tules and cattails will become established. This is indeed muskrat heaven, for these and other aquatic plants are both their food and building materials. The most edible portions of the plants are the roots and the stem portions which are below the surface of the mud. When one of these choice tidbits has been cut free by the muskrat’s sharp teeth, it is carried to some favorite place to be eaten. This may be a mud bar well sheltered by overhanging vegetation from prying eyes, the end of a log projecting above the surface of the water, or perhaps the roof of the “house.” The discarded portion of the stem is buoyant and usually lodges among the remaining plants until needed for building purposes.