Usually, as on the Range Reserve, the rodents are widely distributed over a considerable area. Occasionally, as in the vicinity of Rio Alamosa, N. Mex., as reported by Goldman, they occur only in small colonies.
Plate IV. Fig. 1.—Range Conditions Favoring Kangaroo Rats.
View on higher portion of Range Reserve, showing type of country where Dipodomys s. spectabilis is most abundant. Good growth of grama and needle grasses in October, following summer growth and before grazing off by cattle and rodents.
Plate IV. Fig. 2.—Range Conditions Less Favorable to Kangaroo Rats.
View on lower portion of Range Reserve, where Dipodomys s. spectabilis is less abundant. Vegetation consists principally of Lycium, mesquite, rabbit brush, and cactus, there being very little grass.
HABITS.
EVIDENCE OF PRESENCE.
Mounds.
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 exposure or protection than upon the area occupied by the burrow system which lies within and is the reason for the mound.