150 CALIFORNIA MAMMALS. 



Perodipus agilis Gambel. (Nimble.) 



GAMBEL POCKET RAT. 



Above yellowish bistre mixed with black, the basal half or 

 three- fourths of the hairs slate gray; sides ochraceous buff; 

 tail crested, the hairs toward the end being lengthened, principal- 

 ly on the upper side; upper tail stripe as dark as the back, the 

 lower stripe but little lighter and continuous to the end, but tip 

 usually with white preponderating; soles of hind feet blackish; 

 ankles dull black posteriorly ; ears large ; skull narrow ; supra- 

 occipetal very narrow ; interparietal narrow ; nasals narrow, the 

 outer edges of the posterior half parallel; maxillary arches com- 

 partively narrow. Young; darker, more slaty ; hairs of terminal 

 part of tail not lengthened. 



Length about 288 mm. (11.33 inches) ; tail vertebrae 180 

 (7.10) hind foot 42 (1.65); ear from crown 14 (.55). 



Type locality, Los Angeles, California. 



Gambel Pocket-Rats are common in the coast region of 

 southern California and on the sides of the mountains tO' 3,000 

 feet altitude or higher. They are not often found in brush, 

 or in rocky ground, preferng open valleys having a good growth 

 of annual plants, the seeds and leaves of these plants forming 

 the principal part of their food. Grain is sometimes stored in 

 their burrows, but grain land, especially if summer-fallowed, af- 

 fords too little subsistence in the dry part of the year, and is 

 usually deserted for places where seed producing plants remain 

 on the ground all the year. Occasionally the borders of grain 

 lands are invaded, but the depredations of Pocket-Rats are rare- 

 ly serious, and these are partly balanced by the large amount 

 of weed seeds eaten. 



The following notes on an opened burrow of this species 

 are given to illustrate some of their habits, which are similar 

 to those of Pocket-Rats in general. I had noticed the entrance 

 to a burrow at the side of a path a few yards from the kitchen 

 door of my house; the burrow had been used some months, still 

 the house cat (a very good mouser) had not caught the oc- 



