Arizona \ 
Exp. Sta. I 
LIFE HISTORY OF THE KANGAROO RAT. 
27 
It will be seen from Table 3 that while a large number of 
species of plants are represented in the totals from so many dens, 
a majority of them are of very minor importance, and that the 
seeds of grasses are the principal storage and probably therefore 
the principal food material. Six of the most important species 
of grasses (disregarding species furnishing less than 5 grams) com- 
prise 85.6 per cent of the total weight of storage from 22 dens. 
Crowfoot grama (Bouteloua rothrockii) stands first in quantity in 
the total, forming 39.4 per cent of all stored material, 46 per cent 
of the six important grasses, and 45 per cent of all grasses. The 
largest amount of storage of any one species of grass in any one 
den on the Range Reserve also is of this species, 2.205 grams 3 
(Table 1. den 1, p. 20, and PL VII. Fig. 2). This is exceeded by 
a dropseed grass, Sporobolus cryptandrus strictus, which amounted to 
5.455 grams in a lot from Albuquerque, X. Mex. (Table 1, den 24, and 
PL VIII, Fig. 1). 
Of the species other than grasses found stored in these dens, 
mesquite beans (Prosopis velutina) are most important both by 
weight and number of dens containing them. The total for the 22 
Range Reserve dens is 1.570 grams, or 35.9 per cent of the seeds 
other than grasses, but only 5.1 per cent of the total storage. In 
bulk mesquite beans do not loom up large, as they are probably 
the heaviest material stored. Sections of pods which must have 
been dragged into the burrows are found, some of them certainly 
being much too long for carriage in the pouches. The species of 
plant other than grass found in the largest quantity in any one 
den. however, was Aplopappus gracilis, not recorded in quantity 
from any den until the excavation of the twenty-second, and then 
found in a very large bulk of soft, fluffy material, with most of the 
seeds separated from the heads, and weighing 1,030 grams (Table 1, 
den 22). 
Any of the food materials above listed are likely to be found in 
the cheek pouches, while in addition such extraneous matter as 
stones and feces have also been found. All species of plants stored 
are accessible in the immediate vicinity of the mound, and when any 
particular plant is found seeding in abundance in the vicinity of the 
den it is likely to be represented in the storage. Usually the animals 
can be readily trapped with almost any kind of grain bait, as oats, 
rolled oats, rolled barley, and wheat ; and nut meats also are attrac - 
tive, though Ave have no record of the storing of any true nut in 
the dens, such not being available in the range of the animal on the 
Range Reserve. 
:; This amount of dry grama grass seed (heads) amounts to approximately a bushel. 
