Arizona \ 
Exp. Sta. / 
LIFE HISTORY OF THE KANGAROO EAT. 
35 
probably soon reoccupied even if the original owner is captured, 
and in the course of a few months the reworking of the abode oblit- 
erates the signs of destruction. 
Droppings of the kit fox show an abundance of bones of small 
mammals of kangaroo rat size, among them those of spectabilis. 
Bobcats (Lynx bailey i) and coyotes (Ganis mearnsi) probably 
are a prejudicial factor. Skunks may sometimes be able to surprise 
the kangaroo rats, but probably not often. The western horned owl 
(Bubo virginianus pallescens) , the barn owl (Tyto alba pratincola) , 
and perhaps others may well be among the most feared enemies, but 
no special investigation of owl pellets on the reserve has been possible. 
In 592 barn-owl pellets from California were found remains of 230 
kangaroo rats, only one other rodent being represented by a larger 
number (McAtee, 1921, 258). 
Much more information on enemies is needed. The relatively low 
rate of reproduction (see p. 18) indicates comparative freedom from 
inimical factors. 
PARASITES. 
Oipodomys s. spectabilis is regularly infested with a species of flea, 
Ctenophthalmus sp. Seldom or never is a specimen taken m reason- 
ably fresh condition without some of these parasites present on its 
body, though of course they desert the body of the host after it be- 
comes cold, and hence dead specimens left too long may be free from 
them. The den conditions are ideal for the breeding of this para- 
site, because of the great quantities of fine, dusty, organic refuse 
littering the tunnels and furnishing food and refuge for the larvae. 
As demonstrated to us by F. C. Bishopp. of the Bureau of Entomol- 
ogy, a handful of this refuse taken from the floor of a burrow within 
arm's length of the entrance is almost certain to contain these larvse. 
Less regularly present, perhaps because of its different life his- 
tory, is a small tick, Trombicula sp. At times this parasite is very 
common, being present on nearly every individual rat, and at other 
times specimens are difficult to find : it appears to be more commonly 
present in summer and fall than at other seasons, and is found at- 
tached chiefly to the ears. 
Xo internal parasites have been detected. The nocturnal and fos- 
sorial habits of the animal seem to give complete protection against a 
form of parasite which is very common among some other rodents of 
the Range Reserve, notably Lepus and Sylvilagus. Nearly all rab- 
bits are infested with " warbles," the larvae of a species of bot-fly, 
Cuterebra (family Oestridae). Other small mammals also are occa- 
sionally parasitized by the Cuterebra, but in the handling and exami- 
nation of perhaps 200 or more individuals of spectabilis and merriami, 
we have yet to find a single case of infestation by an oestrid fly. 
