E^pfste.} LIFE HISTORY OF THE KANGAROO RAT. 13 



The ordinary activities of the kangaroo rat in southern Arizona 

 can scarcely be said to show any true seasonal variation. The ani- 

 mals are active all the year in this region, there being neither hiber- 

 nation 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 comparativel}^ 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 onh^ 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. 



PUGNACITY AND SOCIABILITY. 



So far as their reactions toward man are concerned, kangaroo 

 rats are gentle and make confiding and interesting pets; this is 

 especially the case with mema^ni. This characteristic is the more 

 surprising in view of the fact that they will fight each other so 

 readily and so viciously, and yet probably it is explained in part by 

 their method of fighting. They do not appear to use their teeth 

 toward each other, but fight by leaping in the air and striking with 

 the powerful hind feet, reminding one most forcibly of a pair of 

 game cocks, facing each other and guarding in the same manner. 

 Sometimes they carry on a sparring match with their fore feet. 

 Biting, if done at all, is only a secondary means of combat. When 

 taken in hand, even for the first time, they will use their teeth only 

 in the event that they are wounded. The jaws are not powerful, and 

 though the animals may lay hold of a bare finger, with the apparent 

 intention of biting, usually they do not succeed in drawing blood. 

 As Bailey says (1905, 148), they are gentle and timid, and, like rab- 

 bits, depend upon flight and their burrows for protection. 



The well-traveled trails elsewhere described (p. 10) indicate a de- 

 gree of sociability difficult to explain in connection with their pug- 



