As the serious character of the depredations by harmful rodents is recognized, State, Federal, and private expenditures for their control increase year by year. These depredations include not only the attacks by introduced rats and mice on food materials stored in granaries, warehouses, commercial establishments, docks, and private houses, but also, particularly in the Western States, the ravages of several groups of native ground squirrels and other noxious rodents in grain and certain other fi

There are only three groups of mammals in the Southwest having external cheek pouches. These are ( a ) the pocket gophers (Geomyidæ), which have strong fore feet, relatively weak hind feet, and short tail, as compared with weak fore feet, relatively strong hind feet, and long tail in the other two; ( b ) the pocket mice ( Perognathus ), which are considerably smaller than the kangaroo rats and lack the conspicuous white hip stripe possessed by all the latter; and ( c ) the kangaroo rats ( Dipodo

Size large; ears moderate, ear from crown (taken in dry skin) 9 or 10 millimeters; eyes prominent; whiskers long and sensitive; fore feet short and weak; hind feet long and powerful, provided with four well-developed toes; tail very long, usually 30 to 40 per cent longer than the body. Cranium triangular, the occiput forming the base and the point of the nose the apex of the triangle, much flattened, auditory and particularly mastoid bullae conspicuously inflated. General color above, brownish b

Dipodomys spectabilis spectabilis is found in southeastern Arizona, in northwestern, central, and southern New Mexico, in extreme western Texas, in northern Sonora, and in northern and central Chihuahua ( Fig. 1 ). A subspecies, D. s. cratodon Merriam, has been described from Chicalote, Aguas Calientes, Mexico, the geographic range of which lies in central Mexico in portions of the States of Zacatecas, San Luis Potosi, and Aguas Calientes. In the Tucson region spectabilis is typically a resident

One traveling over territory thickly occupied by the banner-tailed kangaroo rat is certain to note the numerous and conspicuous mounds so characteristic of the species, particularly if the region is of the savannah type, grassy rather than brushy. These low, rounded mounds occupy an area of several feet in diameter, and rise to varying heights above the general surface of the surrounding soil, the height depending rather more upon the character of the soil and the location of the mound as to exp

Dipodomys s. spectabilis does not hibernate, so must prepare for unfavorable seasons by extensive storage of food materials. There are two seasons of the year, in southeastern Arizona at least, when storage of food takes place, namely, in spring, during April or May, and in fall, from September to November, the latter being the more important. For the periods between, the animal must rely largely on stored materials. Not infrequently a season of severe drought precludes the possibility of any st

The burrow system, or den, in which spectabilis stores its caches of food materials, has its nest, and remains throughout the hours of daylight is a complicated labyrinth of tunnels. Ejection of refuse and soil from this retreat builds up the mound frequently referred to. These mounds are, as Bailey says, characteristic of the species, and are as unmistakable as muskrat houses or beaver dams, and as carefully planned and built for as definite a purpose—home and shelter. They are, furthermore, th

It is doubtful whether any animals live in a truly commensal relationship with spectabilis , but of not unfriendly associates there are a great number. It is the experience of Bailey, corroborated by observations of Vorhies on living animals, that these kangaroo rats are active in defending their caches of food, and will even fight individuals of the same species savagely and to the death. One moonlight night a strange individual was liberated on a mound. It deliberately entered one of the openi

One's first impression of a well-occupied spectabilis area is that a large family must inhabit each den, but, as previously mentioned, we have gradually been compelled to shift from this conception to the idea of but a single animal to a mound, except when the young are present. Therefore a census of the adult kangaroo rat population can readily be made, simply by counting the mounds. Such a census affords at least a conservative estimate of the number of adult individuals occupying a given area

In May, 1894, Fisher found a ranchman at Willcox, Ariz., who complained more bitterly of the depredations of spectabilis than of those of any other mammal. On the United States Range Reserve the food material appropriated by the kangaroo rat during good years is inappreciable. There is such an excess of forage grass produced that all the rodents together make very little difference. But with the periodic recurrence of lean years, when drought conditions are such that little or no grass grows, th

(1) Kangaroo rats may be separated with ease from all other mammals; the long tail and short and weak fore feet separate them from the pocket gophers; the white hip-stripe distinguishes them from the pocket mice. The decidedly larger size and the white-tipped tail separate Dipodomys spectabilis spectabilis and D. deserti from D. merriami and D. ordii . The darker color and vividly contrasted black-and-white tail of spectabilis distinguish it from deserti . (2) Dipodomys s. spectabilis occurs in

Allen, J. A. 1895. On a collection of mammals from Arizona and Mexico, made by Mr. W. W. Price, with field notes by the collector. Bull. Amer. Mus. Nat. Hist., vol. 7, art. 6, pp. 193-258. 17 figs. in text. Babcock, S. M. 1912. Metabolic water: Its production and rôle in vital phenomena. Research Bull. No. 22, Univ. Wisconsin Agr. Exp. Station, pp. 159 and 170, March. Bailey, V. 1905. Biological survey of Texas. North Amer. Fauna No. 25, Biol. Surv., U. S. Dept. Agr., pp. 222, 16 pls., 24 figs.