The kangaroo rat is strictly nocturnal. An observer watching patiently
by a den in the evening for the animal's first appearance is not
rewarded until darkness has fallen completely, and unless the moon is
shining the animal can hardly be seen. Were it not for the white
tail-brush of _spectabilis_ and its white belly when upright on the hind
legs and tail, one could not as a rule see the animal at all when it
makes its first evening appearance. With the first streak of dawn
activity usually ceases completely and much more abruptly than it began
with the coming of darkness, but on a recent occasion Vorhies observed
that a kangaroo rat which did not appear until near morning remained
above ground until quite light, but not fully daylight. On removal of
the plug from the mouth of a kangaroo rat burrow, one may sometimes see
a fresh mass of earth and refuse shoved into the opening from within. As
often as not, however, even this unwelcome attention does not elicit any
response by day, the great majority of the burrow openings of this
species, as observed by the authors, remaining permanently open.
The ordinary activities of the kangaroo rat in southern Arizona can
scarcely be said to show any true seasonal variation. The animals are
active all the year in this region, there being neither hibernation nor
estivation, both perhaps being rendered unnecessary by the storage
habit, to be discussed in full later (pp. 15-16), and by the mildness of
the winter climate. On any particular night that the weather is rainy,
or the ground too wet and cold, activity is confined to the interior of
the burrow system, and for this reason one has no opportunity to see a
perfect imprint of the foot in freshly wet soil or in snow. On two or
three of the comparatively rare occasions on which there was a light
fall of snow on the Range Reserve a search was made for tracks in the
snow. At these times, however, as on rainy nights, the only signs of
activity were the pushing or throwing out of fresh earth and food refuse
from within the burrow. This is so common a sight as to be complete
evidence that the animals are active within their dens during stormy
weather but do not venture outside. Trapping has again and again proved
to be useless on rainy nights, unless the rain is scant and a part of
the night favorable, in which case occasional individuals are taken.
These statements apply to the Range Reserve particularly; the facts may
be quite different where the animals experience more winter, as at
Albuquerque, N. Mex., although in November, 1921, Vorhies noted no
indications of lessened activity in that region.