Order CARNIVORA 



Skull length less than 100 mm. (4 in.) 



common cat, Felis domestica 



4. Teeth 40 or more 5 



Teeth 38 or fewer 11 



5. Teeth 40; 2 molars on each side of lower jaw 



raccoon, Procyon lotor 



Teeth 42; 3 molars on each side of lower jaw 6 



6. Rostrum short, the anterior end of the nasals midway be- 



tween the orbit and the base of the incisors; last upper 



molar larger than preceding molar 



black bear, Ursus amerlcanusf 



Rostrum long, the anterior end of the nasals much closer to 

 the incisors than to the orbit, fig. 60; last upper molar 

 smaller than preceding tooth 7 



7. Frontal bones each with a depression along mesal side of 



postorb'tal process, fig. 60; skull length less than 150 mm. 



{SVs in.) ^ ^ 8 



Frontal bones each convex, rounding over postorbital proc- 

 ess; skull length usually more than 150 mm. 9 



8. Temporal ridges widely separated posteriorly and lyrate in 



shape, fig. 60^^; inferior margin of lower mandible with 



poster'or "step" or third notch, fig. 60^ 



gray fox, Urocyon cinereoargenteus 



Temporal ridges close together posteriorly, fig. 60a, or ab- 

 sent; inferior margin of lower mandible without pos- 

 terior "step," fig. 60c red fox, f'ulpes fulva 



9. Width of skull across zygomatic arches usually more than 



105 mm. (41/^ in.) ; length of skull usually more than 215 



mm. {%Y> in.) 



timber wolf, Canis lupusf, or red wolf, Canis nigerf 



Width of skull across zygomatic arches usually less than 105 

 mm. ; length of skull usually less than 215 mm 10 



10. Palatal width divided by alveolar length of upper premolar- 



molar series equaling 0.32 or less; rostrum width less than 



18 per cent of skull length:): coyote, Canis latrans 



Palatal width divided by alveolar length of upper premolar- 

 molar series equaling 0.33 or more; rostrum width more 



than 18 per cent of skull length^: 



domestic dog, Cams familiaris 



11. Upper jaw with 5 cheek teeth on each side 12 



Upper jaw with 4 cheek teeth on each side 14 



12. Lower jaw with 5 cheek teeth on each side 



river otter, Lutra canadensis 



Lower jaw with 6 cheek teeth on each side 13 



13. Length of skull less than 90 mm. (31'^ in.) 



pine marten, Maries americanaf 



Length of skull more than 90 mm. . fisher, Martes pennantif 



tThis species is no longer found in Illinois. 



JThese characteristics are evident in relatively pure-blooded animals but plainly 

 will not distinguish between animals which are less than pure blooded. 



