396 THE QUADRUPEDS OF ARIZONA. 
is mouse-gray above and below, and pure white on its 
sides. The fur is peculiarly soft, smooth, and lustrous. 
It chiefly inhabits loose sandy soil, like a gopher, though 
its “sign” differs greatly from that of the last named; 
but it is not entirely subterranean in habit, as it may be 
found living in piles of brush, fallen logs, ete. Though it 
labors at its domicile, and collects food mainly by night, 
it should not be called a nocturnal animal, any more than 
a House Rat, though the latter is liveliest and most 
plaguey after dark. 
Since the erection of buildings in the interior of Ari- 
zona, the Kangaroo Rat has in a measure taken up its 
residence about them, showing the same adaptability to 
semi-domestication that the House Mouse exhibits. Many 
used to live in our storehouses and granaries at Fort 
Whipple, and even brought forth their young there, in 
just such nooks as the common mouse would select. Par- 
turition occurs in May or June, though more than one 
litter may be produced in one season. The young are 
for some time much darker and grayer than their parents. 
Although sullen, and apparently much cowed when fi t 
caught, these rats soon become familiar, and make agree- 
able pets. I have frequently seen them enter my tent 
at night, when all was still, and search about for food. 
They ordinarily move on all-fours, with a motion not 
unlike that of a rabbit when leisurely moving about. The 
body is alternately strongly arched and extended ; the 
long hind feet rest on the ground to the heel, and the 
heavy tail trails straightly after. If frightened, this easy 
motion is changed to a succession of astonishingly vigor- 
ous leaps. Perhaps the most beautiful features of these 
animals are their eyes, which are round and full, glossy 
black, and softly brilliant. 
