266 VERTEBRATE ANIMALS OF THE UNITED STATES 



Mexico and Arizona to Alaska and Hudson Bay; does not climb trees, 

 except when a cub. 



U. horricEus (Baird). Size smaller; the frontal bones flattened and 

 concave between the postorbital process: New Mexico and Arizona to 

 Utah and Colorado. 



U. calif ornicus Merr. Size large; ears longer: central and southern 

 California. 



Family 2. Canidae. — Dogs, wolves and foxes. Body slender, 

 with long legs; feet digitigrade; toes 5-4; claws blunt and non-retractile; 

 head elongate; dentition 3/3, i/i, 4/4, 2/3 (Fig. 139): cosmopolitan; 

 about 50 species in North America. 



Key to the United States Genera 



ai Pupil round; dogs and wolves i. Canis. 



a 2 Pupil elliptical; tail bushy; foxes. 



bi Tail with soft under-fur 2. Vulpes. 



bo Tail with coarse fur 3. Urocyon. 



I Canis L. Dogs and wolves. Legs long; tail moderately bushy; 

 upper incisors distinctly lobed: many species; cosmopolitan; about 24 

 in North America, and 15 in the United States. The domestic dog, 

 C. familiaris, is descended from a number of wild stocks. The native 

 wild dogs and wolves fall into 2 groups or subgenera, one of which is 

 Canis L. and has for its characteristic representative <he gray wolf, and 

 the other is Lyciscus Hamilton Smith, which is represented by the 

 coyote. They are very prolific, wolves having sometimes as many as 

 12 young at a birth and coyotes as many as 14. 



Key to the United States Species of Canis 



ai Size large; wolves; length mostly over 1,400 mm. 

 bi East of the Mississippi. 



Ci In the northeastern States C. lycaon. 



C2 In the southern States C. floridanus. 



bo West of the Mississippi. 



Ci On the Great Plains and in Rocky Mountains; tail short. .C. nubilns. 



Co In the Puget Sound region C. gigas. 



C3 In Texas C. frustror. 



C. rufus. 

 ao Size smaller; coyotes; length under 1,200 mm.; muzzle sharp. 



bi On the northern prairies C. latrans. 



bo On the Great Plains C. nebracensis. 



ba In the mountains and the Great Basin C. lestes. 



hi In the southwest. 



Ci In the lower Rio Grande Valley C. microdon. 



02 In Arizona C. mearnsi. 



