STREATOR WOOD RAT. Neotoma fuscipes streatori Merriam

Field characters.—Form and size about those of House Rat, but tail shorter than head and body (fig. 13); tail round, closely haired, not bushy (fig. 12b); pelage soft and smooth; ear rather large, rounded. Head and body 7-1/4 to 8-1/4 inches (183-209 mm.), tail 6-1/2 to 7-1/2 inches (165-191 mm), hind foot about 1-1/2 inches (35-38 mm.), ear from crown 1 to 1-1/4 inches (24-32 mm.), weight 7-1/4 to 8-3/4 ounces (206-247 grams). Coloration brownish gray with a general overlay of black hair tippings; whole under surface of body, under side of tail, and upper surface of feet, white.

Workings.—Nests or 'houses,' 2 to 3 feet high, conical in shape, composed of twigs, leaves, chunks of wood, etc.; placed on ground beneath brush plants or trees, or, less often, on horizontal branches of oak trees at height of several feet from ground. Droppings: Cylindrical, about 3/8 inch long and 1/8 inch in diameter, scattered in and about nest, or at intervals along runways.

Occurrence.—Common resident chiefly in Upper Sonoran Zone and lower part of Transition Zone, on west slope of Sierra Nevada. Recorded from Snelling and Pleasant Valley eastward to floor of Yosemite Valley. Lives in mixed stands of trees and brush, occasionally among rocks. Chiefly nocturnal.

Fig. 12. Tails of (a) Alexandrine Roof Rat, (b) Streator Wood Rat, and (c) Gray Bushy-tailed Wood Rat. One-half natural size.

The Streator Wood Rat is well known to residents of the foothill country of east-central California. The animal itself is seldom seen, but evidence of its presence in the form of large nests or 'houses' is to be observed in many places. This animal is often referred to as 'pack rat' or 'trade rat' by reason of its propensity for carrying articles from place to place in and about cabins or camping places.

The Streator Wood Rat is close to the house rat in size, the length of body and the weight being about the same in the two; but the wood rat's tail is shorter than its head and body, while the reverse is true of the roof rat. The pelage of the wood rat is rather short, with no conspicuous coarse over-hairs; it is dense and even, and feels soft to the touch. The coloration above varies from blue gray in the younger animals to sandy brown in adults. Very large males become suffused with reddish or huffy brown, particularly on the sides of the body. On the whole under surface of the body and tail at all ages the fur is pure white. Although streatori is grouped with the brown-footed wood rats, its feet are pure white, as is also the lower half of its tail. The tail of the Streator Wood Rat is well haired and hence quite different in appearance from the scaly tail of the roof rat; but the hairs on the tail of streatori are short and closely laid, with no long hairs on the sides of the tail as in the Bushy-tailed Wood Rat. (See figs. 12b, 13.)

The Streator Wood Rats are active chiefly by night, so that sight of one is seldom obtained. Most of our information relating to the rats themselves was gained by setting traps baited with rolled oats near nests or other places which showed signs of recent occupancy by the animals. The individuals taken for specimens were all trapped during the night-time. Only three of the animals were noted abroad during the daytime and on each occasion the rat was in view for but a few seconds. At El Portal, in early December, one was seen to run into a brush pile on the hill above the river; near Cascades in November a wood rat appeared while one of our party was 'squeaking' at a Winter Wren; and near Coulterville an adult wood rat was frightened from its nest while one of our party was dismantling the structure.

The 'round-tailed' wood rats are active throughout the year, so far as we know; trapping at any season is likely to produce specimens. In Yosemite Valley tracks of the Streator Wood Rat were seen in snow on the Yosemite Falls Trail on December 9 (1914). In midwinter, when snow covers the exterior of the rock slides on the Valley walls, the wood rats are able to run about in comfort and safety in the spaces between and beneath the granite blocks.

Fig. 13. Streator Wood Rat. Photographed from fresh specimen trapped near foot of Yosemite Falls trail in Yosemite Valley, November 22, 1915. About 1/3 natural size.

Usually the wood rats obtained for specimens were trapped close to nests, but in one instance an immature individual was taken in a trap set on the ground beneath chaparral in a place where no evidence of wood rat activity was to be seen. At El Portal there were indications that the wood rats were using the trails made by the brush rabbits through and beneath the greasewood chaparral. These rats have regular paths or trails of their own, especially along the walls of narrow ravines. These paths are kept more or less bare of leaves, evidently by the frequent passage of the animals over them. At Dudley the rail fences through dense chaparral were being used regularly as highways; the lower rails were chosen rather than the uppermost one, doubtless on the principle of "safety first." At Kinsley, droppings of wood rats were found in the farthest recesses of a cave some 50 feet from its entrance. Animals living there would have to seek territory for foraging altogether outside the cave.

The most conspicuous feature in the life history of the Streator Wood Rat is its propensity to build houses. These structures are usually conical in shape and measure from 18 inches to 3 feet in height, having the same or a slightly greater diameter at base. A majority of the houses are built on the ground, among or beside brush plants, but seldom far away from such trees as live oaks and willows. Sometimes the nests are placed on horizontal branches in oak trees at heights of as much as 15 feet above the ground. Less often the animals live among the rocks, and then the shape of the house or nest is accommodated to the crevices available between adjacent slabs or boulders. Now and then the structure is heaped around a downed tree, as described below; and in one case a nest was found in the hollow trunk of a living black oak.

The usual wood rat nest is only a pile of various sorts of material of such kinds as can be accumulated from the near vicinity of the site. Within there is a nest chamber of varying size and proportions. The houses sometimes have underground retreats or passageways, as through a hollow tree root, so that in time of danger the wood rat can escape from the nest without appearing on the surface of the ground until it is some distance away. Entering into the composition of different houses in the Yosemite foothills we found the following materials: twigs and green cuttings of Ceanothus cuneatus, C. integerrinus, buckeye, live oak, golden oak, yellow pine, and willow, reed stalks, cones of yellow pine, chunks of decayed wood, and, in one case, stones each weighing several ounces.

On a digger-pine-covered hillside which had been burned over within a year, near the McCarthy ranch, 3 miles east of Coulterville, a house of the Streator Wood Rat was found and studied, June 2, 1915. (See fig. 14.) This structure had been built on and partly within a rotten log which lay on the ground. There was a thatch of dry sticks and pieces of bark from the digger pine, and this covering seemed to have protected the interior of the nest effectively against moisture. At one end of the log was an entrance to the interior and here was accumulated a mass of droppings and other debris which the animals had removed from within the house. Inside the house, partly or completely inside the log, were no less than four beds or nests proper; only one of these was occupied when the place was examined. The beds were composed of shredded wood, dry twigs and grass stems, and some green leaves. In one place a quantity of fresh young leaves of the golden oak was found. Three holes led out from the main interior cavity of the house, one of these going down lengthwise of the log, while the two others went into the ground.

Fig. 14. Sketch showing interior arrangement of nesting quarters of a Streator Wood Rat in a hollow log. Locality, three miles east of Coulterville, June 2, 1915.

In one of the beds a very young wood rat was found; and an adult animal ran out of the same nest as the place was opened up. No other wood rats were seen nor had any been trapped adjacent to this log during the few days preceding, so it seems likely that the place was tenanted by just the two. Part of the interior of the nest contained a mouldy mass of old droppings and bits of twigs, and fresher droppings were found about the beds. The animals seem to exercise none of the precautions for cleanliness observable in some rodents, for example, pocket gophers. The damp earth beneath one nest abounded in fleas, though none of these pests were to be seen on the young wood rat which was found in this nest.

The breeding season of the Streator Wood Rat, to judge from the capture of strictly juvenile specimens, includes most of the warm months of the year. Thus, a juvenile animal trapped at Pleasant Valley on May 19 (1915) points to an early commencement of breeding activity, possibly in March; whereas an immature specimen captured on November 24 (1915) near Cascades could not have been born earlier than September. Trapping in May and June, however, gave evidence that the greatest amount of breeding activity occurred at about that season. Most of the females taken then were suckling young, and two nests examined each held a single young animal. A female collected May 24 at Pleasant Valley contained one embryo, and another obtained June 1, 3 miles east of Coulterville, contained 2 small embryos. By late autumn (November), young born during the current year weigh about 5 ounces (150 grams), which is about three-fifths the weight of adults.