SMALLER MAMMALS OF NORTH AMERICA 



545 



these animals through parts of several sur- 

 rounding counties. The United States Public 

 Health Service and the local authorities in a 

 vigorous campaign stopped the spread of this 

 malady, but not until the potential ability of 

 these rodents as plague-carriers had been well 

 established. This fact and the wide distribu- 

 tion of the California and other ground squir- 

 rels over a large part of the continent should 

 not be overlooked in connection with possible 

 future outbreaks of the plague. Fortunately, 

 investigation and field experiments on a large 

 scale have shown that these spermophiles may 

 be destroyed by poison over great areas at a 

 relatively small cost. 



THE ANTELOPE CHIPMUNK (Ammo- 

 spermophilus leucurus and its relatives) 



{for illustration, see page S39) 



Commonly known as the antelope, or white- 

 tailed, chipmunk, this handsome little mammal 

 is in reality a species of spermophile, or ground 

 squirrel. The misnomer is due, no doubt, to 

 its small size, striped back, and sprightly ways. 

 From the true chipmunks it may be distin- 

 guished by its heavier proportions, and from 

 both chipmunks and all other spermophiles by 

 its odd, upturned tail, carried closely recurved 

 along the top of the rump. This character 

 renders the species unmistakable at a glance 

 and gives it an amusing air of jaunty self-con- 

 fidence. 



The antelope chipmunk is characteristic of 

 the arid plains and lower mountain slopes of 

 the Southwest from western Colorado through 

 Utah, northern Arizona, Nevada, the southern 

 half of California, and all of Lower California, 

 and down the Rio Grande Valley through New 

 Mexico to western Texas. 



Within this area it occupies a wide variety 

 of situations. It inhabits the intensely hot 

 desert plains near sea level in Lower Cali- 

 fornia, where the temperature rises to more 

 than 125 degrees Fahrenheit in the shade and 

 the vegetation is characterized by such pic- 

 turesque forms of plant life as cactuses of 

 many species, yuccas, fouquerias, palo verdes, 

 ironwood, and creosote bushes ; it is found also 

 above 7,000 feet altitude on the cool plateaus 

 and mountain slopes of Arizona and Colorado, 

 among sage brush, greasewood, junipers, and 

 pihon pines. It appears equally at home skip- 

 ping nimbly over rocky slopes or among slide 

 rock in arid canyons and scurrying through the 

 brushy growth on broad sandy plains devoid 

 of rocks. 



The antelope chipmunk has the most vivacious 

 and pleasing personality of all the numerous 

 ground sejuirrels within our borders. During 

 the many months I have camped and traveled 

 on horseback in their haunts I have never lost 

 interest in them. They were forever skirmish- 

 ing among the bushes or dashing away down 

 trails or over the rocks of canyon slopes, their 

 white tails curled impudently over their backs 

 like flags of derision at my cumbersome ad- 

 vance. 



Their burrows are dug in a variety of places. 

 In the open flats they enter the ground almost 

 vertically, and often several entrances are 

 grouped within a few yards. In some places a 

 little mound of loose dirt is heaped up at one 

 side of the entrance and at others there is no 

 trace of it. Frequently, when the ground is 

 soft, little trails lead in different directions 

 from the entrances, and often between holes 

 100 yards or more apart, as though they made 

 many social visits. The deserted burrows of 

 other mammals are sometimes utilized to save 

 the trouble of digging. The burrows are often 

 under the shelter of cactuses, bushes, and great 

 boulders or may be among crevices in the rocks. 

 _ Antelope chipmunks are extraordinarily ac- 

 tive and continually wander far from home in 

 search of food or in a spirit of restless in- 

 quiry. As the traveler on horseback rides 

 slowly along he will see them racing away in 

 front of him, sometimes climbing to the top of 

 a bush 100 or 200 yards in advance for a better 

 look at the wayfarer and then scuttling down 

 and racing on again. In this way I have seen 

 them keep ahead of me sometimes for several 

 hundred yards instead of hiding in some hole 

 or shelter, as they might easily do. At other 

 times they were so unsuspicious they would 

 permit me to pass within a few yards with 

 slight signs of alarm. They have a chirping 

 call, often uttered when watching from the 

 top of a bush, and also a prolonged twittering 

 or trilling note, diminishing toward the end. 



In the higher and colder parts of their range, 

 where snow lies long on the ground, these 

 spermophiles hibernate for several months, but 

 in the warmer areas they are active throughout 

 the year. Wherever they occur they gather 

 food and carry it to their underground store- 

 rooms in their cheek pouches. Like most 

 ground squirrels, they eat many kinds of seeds 

 and fruits as well as flesh and insects when 

 occasion offers. About cultivated lands they 

 are sometimes abundant and destructive, dig- 

 ging up corn or other grain as soon as it is 

 planted and also taking toll of the ripening 

 grain until they become a pest. In the desert 

 they often gather about camps to pick up the 

 grain scattered about when the horses are fed. 



It is well for them that they are prolific, 

 having one or more litters during spring and 

 summer, with from four to twelve in each, as 

 they have many enemies. Snakes and weasels 

 pursue them into their burrows, while foxes, 

 coyotes, l)adgers, bobcats, and many kinds of 

 hawks, constantly reduce their numbers. | 



THE GOLDEN CHIPMUNK (Callosper- 

 mophilus lateralis chrysodeirus and its 



* relatives) 



(For illustration, see page 542) 



The golden chipmunk, or calico squirrel, as it 

 is named in Oregon, is the most richly colored 

 of the several geographic races of a widely 

 known species, C alios perm ophiliis lateralis, 

 abundant among the open forests of yellow 

 pines and firs of the western ranges, including 



