g season is the
less important, the plants consisting chiefly of a variety of small
annuals, while the important range grasses make their chief growth and
head out almost exclusively in the July-August rainy season. It may be
noted also that the actual increases in storage appear somewhat after
the growth period proper, since storing does not get well under way
until the seed crop is mature. The banner-tailed kangaroo rat shows a
marked adaptability to different foods available in the neighborhood of
its burrows. It must, perforce, adapt itself and its storage program to
the food that it can get, and this varies enormously with the climatic
conditions of successive seasons. The large numbers present in suitable
localities clearly indicate that the animal is successful in meeting the
changing and sometimes extremely adverse conditions of its environment.

[Illustration: PLATE VIII. FIG. 1.--CONTENT OF DEN EXCAVATED IN NEW MEXICO.

Storage content of Den No. 24, of Table 1, from Sandia Mountains, N.
Mex. This is the largest lot of storage taken in the course of the
investigations. The larger pile consists wholly of a valuable grass,
_Sporobolus cryptandrus strictus_: the smaller of Russian thistle
(_Salsola pestifer._)]

[Illustration: PLATE VIII. FIG. 2.--GROWTH FOLLOWING ELIMINATION OF
KANGAROO RATS.

The same mound as shown in Plate III, Figure 1, after three years of
protection, the rodents having been killed out. Nearly as good grass
recovery following poisoning operations occurred in the single excellent
season of 1921.]

At times, more especially in the seasons of active growth, some of the
green and succulent portions of plants are eaten. This was very
noticeable in the spring of 1919, when a most luxuriant growth of
Mexican poppy (_Eschscholtzia mexicana_) occurred. Stomachs at this time
were filled with the yellow and green mixture undoubtedly produced by
the grinding up of the buds and flowers of this plant. Small caches of
about a tablespoonful of these buds were also found in the burrows at
this time. Occasionally in spring one may find a few green leaves of
various plants, _Gaertneria_ very commonly, tucked away in small pockets
along the underground tunnels, indicating that such materials are used
to some extent. As has been shown in detail, however (Table 1), the
chief storage, and undoubtedly the chief food, consists of air-dry
seeds.

The character of the storage, the absence of rain for month