132 



NORTH AMERICAN FAUNA 66 



in the coyote and usually shorter and more blunt in the dog. In addi- 

 tion, the tips of the upper canines of the coyote fall below the level of 

 the anterior mental foramina when the jaws are closed; in the dog 

 they terminate above these foramina. The premolar teeth in the coyote 

 are generally widely space ; in the dog they are crowded. The ventral 

 surface of the mandibular ramus is flattened in the coyote, whereas in 

 the dog it is generally rounded. Various indexes have been developed 

 to express numerically some of the above-mentioned cranial differences 

 (see Howard, 1949, p. 171 ; Bee and Hall, 1951, pp. 73-77 ; Burt, 1946, 

 pp. 61-62). 



Certain specimens exhibit a confusing combination of dog and 

 coyote characteristics. These animals may represent hybrids, but the 

 characteristics of known hybrids have not been adequately documented. 

 Until the problem of hybridization between the coyote and dog is 

 thoroughly studied it seems advisable to refer any questionable speci- 

 mens to the latter species. The domestic dog is one of the most variable 

 animals with regard to its physical structure, whereas the coyote is 

 a very uniform one (except for size) . Because of this, it is possible for 

 the domestic dog to exhibit some coyote traits without having any ad- 

 mixture of coyote blood, whereas it is far less likely that a coyote would 

 exhibit dog traits without some dog intermixture. 



In the field, the coyote at a distance may resemble a gray wolf ( Canis 

 lupus). The coyote, however, is much the smaller animal, has a more 

 yellowish cast to the pelage, and carries its tail lower when running. 

 The skull of the coyote is smaller than that of the gray wolf, and more- 

 lightly built ; the teeth are much smaller, and the frontal region of the 

 skull is flat, whereas in the gray wolf it is bulging as in the domestic 

 dog. 



Both the red fox and the gray fox are less doglike in general appear- 

 ance than the coyote, and both are considerably smaller in size, and 

 different in coloration. 



Measurements. — Externally the coyote ranges in total length from 

 1,052 to 1,320 mm. with a tail varying from 300 to 394 mm. The hind 

 foot averages between 177 and 220 mm. (Hall and Kelson, 1959, p. 

 843) . Animals from southwestern localities are smaller than those from 

 farther north, and males are larger than females. 



A male from 5 miles northwest of Poolesville, Montgomery County, 

 and a female from Cecil County, near the Delaware State line, west 

 of Middlebury, Del., have the following cranial measurements : Condy- 



lobasal length 180.4, ; zygomatic breadth 99.8, 87.8 ; interorbital 



breadth 29.6, 31.5 ; length of maxillary toothrow 82.3, 78.7. 



Habitat and hahits. — ^The coyote prefers open or semiopen country. 

 Young (Young and Jackson, 1951, p. 11) calls the coyote an "edge" 

 animal, and believes that it has expanded its range as the forested 



