CALIFORNIA FISH AND GAME 199 



may have been diseased. However, in the two younger does with 

 antlers I have been unable to find any evidence that the reproductive 

 organs were aberrant. Furthermore, both of these younger does had 

 hard, normal, symmetrical antlers free of velvet. 



EARS 



The mule deer possesses the largest ear in proportion to body size 

 of any of our North American deer. This is most conspicuous in the 

 adult doe (see Fig. 57). This character has been utilized in the scien- 

 tific names hemionus, which may be freely translated as "half mule," 

 and macroUs, which means "large ears." Not only is this member of 

 large size but it is so controlled by a muscular arrangement as to be 

 instantly adjusted to catch the slightest sound coming from any direc- 

 tion (see Fig. 58). 



The inside of the ear of the Rocky Mountain mule deer is well 

 covered with long silky hair, light gray in general color. The outside 

 covering is a shorter, stiffer covering of darker hairs. There is a gen- 

 eral tendency toward rich dark brown color around the outer rim of 

 the ear and particularly on the back of the ear (see Figs. 57 and 58), 

 The black edging of the ear is much less conspicuous in the newly born 

 fawn than it is in the adult, but comparison between the sexes shows 

 that even in day-old fawns the males usually show more tendency 

 toward the dark coloration than the females, which are lighter in color. 



In none of our North American deer is the flexibility in movement 

 of ears as great as it is in the mule deer. It would seem probable 

 that there is a close interrelation between type of habitat and the 

 development in the size of the ear. The burro deer and certain Rocky 

 Mountain mule deer living in extreme open desert country have been 

 found to possess the maximum ear development, whereas the California 

 and southern mule deer, which live in dense brush habitats, have ears 

 of smaller size that are scantily covered with a growth of stiff hairs. 



TAIL 



All forms of mule deer which occur in California have a character- 

 istic type of tail, the tail being cylindrical in general form and the 

 terminal half consisting of long black hairs. In typical Rocky Moun- 

 tain mule deer, this tuft of black hairs occupies only the terminal half 

 of the tail, the upper portion of the tail being creamy white on the 

 dorsal surface and sides and normally naked part way doAvn the under 

 side. In many instances as the hairs become abraded there is a decided 

 narrowing of the tail at its middle (see Fig. 59). 



The tail of a mule deer doe (Mus. Vert. Zool. No. 35,326) killed 

 by W. D, Johnson on September 11, 1925, at a point four miles east of 

 Sierraville and twenty-six miles northwest of Truckee, measured seven 

 inches in length exclusive of hair, and was typical of a Rocky Moun- 

 tain mule deer. In extreme examples of the Rocky Mountain mule 

 deer, the terminal black tip does not occupy more than one-third of the 

 tail. On the other hand, in many specimens of California mule deer, 

 the black terminal tip is continued as a distinct black stripe that 

 extends clear to the base of the tail. As a matter of fact, this charac- 

 ter was given by the original describer, Caton, as one of the outstanding 

 characteristics of this form. It has been my experience that, in general, 



