Distribution.—Northeastern Washington and the Blue Mountains of southeastern Washington, extending west, in northeastern Washington, to Conconully (W.W.D.) and south to Duly Lake (W.W.D.).
Neotoma cinerea Ord
Bushy-tailed wood rat
Description.—The bushy-tailed wood rat is slightly larger than the common Norway or brown rat. The head and body measure about 12-1/2 inches and the tail about 3-1/2 inches. It resembles the deer mouse in general proportions. The ears are large and naked and the black eyes are large and protruding. The tail is bushy, squirrel-like. The feet are small and have furry soles. The fur is soft and silky. Adults are brownish gray above with white underparts and a gray tail. Young individuals have blue-gray upper-parts.
Wood rats range over most of North America. They exhibit great variation, especially in the southwestern United States. The bushy-tailed species occurs in the western United States and Canada. Wood rats are notorious for invading buildings in the mountains and in the desert. However, their natural habitat is broken rock or talus. This habitat preference accounts for their distribution in Washington, for talus is common except in the humid subdivision of the Transition Life-zone. Wood rats are probably most abundant in the talus slides of the Columbian Plateau, especially in the canyon of the Columbia River and in Moses and Grand coulees. They are common in all the mountainous areas in the state where high altitudes and steep slopes result in the accumulation of talus. Wood rats range from sea level to 10,000 feet elevation on Mount Rainier and from the Upper Sonoran to the Arctic-alpine life-zones. Great horned owls and probably all of the carnivores that share the range of the wood rat prey on it to some extent. [Sperry] (1941: 15) lists Neotoma in four per cent of 8,339 coyote stomachs gathered throughout the United States.
Wood rats in Washington are definitely nocturnal and are rarely seen in daylight. On January 10, 1939, however, near Colville, Stevens County, a companion and I were sitting on the porch of a deserted shack eating lunch. Suddenly a wood rat darted out of the open door into the full sunlight and tugged at a can, containing a few drops of tomato juice, which one of us was holding in his hand. When the rat looked up and saw the human, it hastily retreated. The wood rat has a habit of flattening its body tightly against the ground when observed and also of "drumming" with its feet when excited. This habit is shared by the snowshoe rabbit and the spotted skunk. A captive specimen "drummed" by lifting its back feet, alternately, about one-half inch from the surface of a piece of wood and striking downward with surprising power. The agility of the wood rat was demonstrated near Wallula where we watched a specimen by the light of a flashlight as it climbed an almost vertical rock wall, taking advantage of small fractures for toe-holds.
Wood rats are far from noiseless in their nocturnal activities. Near Moses Coulee, Douglas County, wood rats were heard from a distance of 50 feet as they scampered back and forth through a concrete culvert under the highway.
Many species of wood rats build complicated stick houses in which they live. In Washington, elaborate stick houses are sometimes built but are usually not occupied. In the attic of an old building near Pend Oreille Lakes, Stevens County, two large and complicated houses were discovered. These were built of sticks, paper and other debris and measured more than three feet in diameter. Three small, cup-shaped nests resembling those of a bird, made of soft grasses, moss, and shredded paper were found on the attic floor ten feet or more from the stick houses. These nests gave every indication of being used, while the piles of sticks contained no nests and seemed never to have been occupied. Near Moses Lake, Grant County, a wood rat house built in the rafters of an old shed was constructed entirely of tumbleweeds (Salsola pestifer). This house was spherical in shape and measured more than five feet in diameter. It appeared to be unoccupied and a wood rat, probably its builder, was living under the floor of the shed. Most wood rat houses consist of a half-dozen sticks arranged in a crevice in a rock pile or a cave. Wood rats were placing fresh material on a house in the Wenatchee National Forest on January 17, 1939, when there was two feet of snow on the ground and the temperature was hovering around zero. The house measured about one cubic yard and consisted of Ceanothus leaves and steins, with some twigs of fir (Abies). It was built under a bunk in a broken-down cabin left by deer hunters.
The collecting habit of the wood rat has gained it the name "pack-rat." [Taylor] (1920A: 91) lists the following materials from a wood rat nest on Mt. Rainier: Nesting material: rags, leaves, paper, thumb of a glove, string, thongs, oakum; Food: apple core, onion peel, bacon rind, raisins, 10 bars of chocolate, figs, puff balls, bread crust, meat scraps, cantaloupe rind, potatoes, dried apricots, lemons, mushrooms, beans, peanuts, banana, 15 lumps of sugar; Miscellaneous: dime, coffee can cover, paraffin from jelly glass, bones, 19 pieces of candles and several cakes of soap.
As a rule only one or two wood rats are trapped at a given locality, indicating that the species is not gregarious. The presence of wood rats in a building, cave, mine tunnel, or talus slide can be detected in several ways. The white, mineral-like incrustation formed by the urine of many generations of wood rats is usually conspicuous on rocks near their homes. A strong musky odor pervades the atmosphere in every habitat occupied by wood rats. Wood rat feces, consisting of hard, black cylinders one-half inch long and three-sixteenths of an inch in diameter, are invariably found scattered on stones or exposed areas of ground.