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MAMMALS OF AMERICA 



WHITE-SIDED JACK "RABBIT' 

 Lepus alleni Mcarns 



Other Names. — Allen's Jack " Rabbit." Antelope 

 Jack " Rabbit." 



General Description. — A very large Hare with 

 extremely large ears and hind legs, white mottled sides, 

 black tail. Head large and broad ; ears enormous, well- 

 clothed with short hair; body large; tail short, marked 

 with black ; pelage quite long and thick. A desert 

 animal. 



Dental Formula. — Incisors, ^^: Canines,——; Pre- 

 molars, ^-^ ; Molars, f -^=^8. 



2 — 2 ' 3 — 3 



Pelage.— Adults : Se.xes identical. Seasonal varia- 

 tion not especially conspicuous. Above yellowish-brown 

 mi.xed with black; nape of neck fulvous; sides, hips, 

 rump and outside of legs white mixed with black, giving 

 a salt and pepper effect ; a fulvous band across chest, 

 rest of underparts white; head, pale yellowish-gray; 

 feet above white ; tail above like back but with a line of 

 plumbeous-black extending onto it from the rump, 

 beneath white ; ears whitish with white fringe. Young : 

 Very similar to adults. 



Measurements.— Total length, 26 inches; tail verte- 

 brae, 2.5 inches ; hind feet, 5.5 inches ; ear from notch, 

 6.2 inches. 



Range.— Desert plains of southern Arizona south 

 into Mexico. 



Food. — Desert vegetation. 



Remarks. — Allen's Jack "Rabbit" typifies one of the 

 most highly specialized groups of North American 

 Hares. This group contains some 12 species and sub- 

 species to be found north of the Rio Grande, most of 

 which have the characteristic black tail, and for this 

 reason are known as Black-tailed Jack " Rabbits." 

 None of this group becomes white in winter, and all 

 are desert or semi-arid plains types. Classification of 

 this group is based to a considerable extent on cranial 

 characters which are correlated often with noticeable 

 variations in color and in proportions of different parts. 



Rel.\ted Species and Subspecies 



Allen's Jack " Rabbit." — Lcpus alleni alleni 

 Mearns. Typical animal of the above description. 

 Desert plains from southern .Arizona south into 

 Mexico. 



Sinaloa Jack "Rabbit." — Lepus alleni palitans. 

 Bangs. Skull largest of American Hares; ears long; 

 tail less black above ; sides of head and back bright 

 cream to pinkish-buff. Pacific Coast to Mexico. 



Gaillard's Jack " Rabbit." — Lepus gaillardi gaillardi 

 Mearns. Ears enormous; above pale ochraceous- 

 cinnamon mixed with black ; tail above, black with many 

 white-tipped hairs. Grassy plains of southwestern New 

 jMexico southward. 



Also see Black-tailed group which follows. 



The White-sided Jack " Rabbits " are perliaps 

 the most striking and the handsomest of all the 

 North American Hares. They differ from 

 others in having the sides mottled white, the 

 hindquarters being tisually gray, and ito black 

 patch en the back of the ear-tips. In Nelson's 

 opinion, " it is safe to assume that the white on 

 the sides serves the same purpose in all these 

 species. By means of muscles the skin of either 

 side can be drawn over the back at will. In this 

 manner the huffy or brown dorsal area is shifted 

 more or le.'.s completely to one side and the white 

 on the opposite side is drawn nearly or quite to 

 the median line. This habit has been observed 

 when the Hares were standing, or moving along 

 at moderate speed, usually after they had been 

 driven from their forms. This enlargement of 

 the white area is always on the side turned 

 toward the chance intruder, and accordingly 

 alternates from side to side as the animals 

 slowly zigzag away. In the bright sunlight the 

 snowy white side flashes brilliantly, attracting 

 attention from afar, and affording a fine ex- 

 ample of directive coloration." 



This group of Jack Rabbits r.T.iges from the 

 southern portion of the State of Arizona and 



the extreme south of New Mexico to beyond 

 the isthmus of Tehtiantepec. It may in fact be 

 considered a Mexican group. Individuals are 

 found at sea level and at various altitudes up to 

 about 8500 feet. They live commonly on open 

 plains. 



Allen's Jack " Rabbit " is one of the largest 

 and handsomest of the White-sided group. It 

 is about twenty-six inches in length, has 

 enormous ears, long and slender legs, and, with 

 the exception of the Sinaloa Jack Rabbit, the 

 largest skull of any American Hare. The strik- 

 ingly bright color of its coat completely dif- 

 ferentiate:, it from the other species. It has 

 been noticed that the richness of coloration in- 

 creases in intensity to the southward, while " the 

 pale typical form is limited mainly to the hot 

 plains of southern Arizona." 



Concerning its habits, Mr. W. W. Price says : 

 " This splendid Hare is abundant about Tucson 

 and in lower portions of the desert belt. It is 

 somewhat shy. and hard to secure, except with 

 a rifle. One rarely comes upon it suddenly. It 

 has a slow, apparently awkward gait, but its 

 leaps are long, and it gets over the ground with 

 surprising ranidity." 



