Family CANIDAE 117 



The skull of the coyote is 180-200 mm. (7-8 inches) long; 

 its zygomatic breadth is 97-110 mm. (3^4-4j4 inches). Dental 

 formula: I 5/i f C 1/1, Pm 4/4, M 2/3. 



Coyotes and dogs may cross or hybridize. Several hybrids of 

 these animals are known from Illinois. In size, markings, and 

 bearing, they naturally are somewhat intermediate between 

 the coyote and dog parents. It is possible to distinguish skulls 

 of some coyotes, dogs, and first generation coyote-dog hybrids 

 by taking certain cranial measurements and -determining cranial 

 indices. Obviously, skulls with intermediate or near-interme- 

 diate measurements are from animals' having both dog and 

 coyote ancestry. Convenient indices and formulas for deriving 

 them are shown below: 



Cranial Index 



Formula Coyote Hybrid Dog 



Palatal width between inner margins 

 of alveoli of upper first premolars 



X 100 25-32 32-38 32-52 



Alveolar length of upper premolars 



and molars 



Width. of basioccipital bone 



X 100 23.3-28.1 28.0-29.1 29.1-34.3 



Width of braincase 



Depth of lower jaw below- 

 second molar 



X 100 12.2-14.1 14.2-14.7 14.0-17.8 



Length of lower jaw 



The coyote of Illinois can be distinguished from the timber 

 wolf of Minnesota or Michigan by its smaller size (less than 62 

 inches over-all length not including hair on tip of tail), nar- 

 rower nose pad (less than \\4> inches in width), smaller feet 

 (each hind foot less than 10 inches long), smaller skull (length 

 less than 8 1 4 inches), and smaller teeth. The timber or gray 

 wolf does not now occur in Illinois. 



Life History. — Although the coyote may never have been 

 abundant in Illinois, it does not seem to have suffered much 

 from the settlement of the land by man. In fact, it may have 

 profited by the opening up of the land. Over a recent 5-year 

 period, 65 coyotes were taken in Fulton County, central Illinois, 

 according to a report by Anderson (1951:172). Since coyotes 

 are interbreeding with dogs, and several hybrids have already 

 been taken in Illinois, it will be interesting to determine if the 

 number of crosses increases. 



