ex., as reported by Goldman, they occur only in small
colonies.

[Illustration: 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.]

[Illustration: 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.

A den in sandy soil in the open may be of maximum size in area occupied
and yet scarcely present the appearance of a mound in any sense, due
probably both to the fact that the sandy soil will not heap up to such a
height over a honeycomb of tunnels as will a firmer or rocky soil, and
also to its greater exposure to the leveling action of rains and the
trampling of animals. These mounds are in themselves large enough to
attract some attention, but their conspicuousness is enhanced by the
fact that they are more or less completely denuded of vegetation and are
the centers of cleared areas often as much as 30 feet in diameter (Pl.
V, Fig. 1); and further that from 3 to 12 large dark openings loom up in
every mound. The larger openings are of such size as to suggest the
presence of a much larger animal than actually inhabits the mound. Add
to the above the fact that the traveler by day never sees the mound
builder, and we have the chief reasons why curiosity is so often aroused
by these habitations.

On the Range Reserve the mounds are usually rendered conspicuous by the
absence of small vege