DECIDUOUS NATURE OF DEER ANTLERS 355 



which was protected from freezing for a number of \ears de\'eloped 

 numerous accessory branches leading to the production of massi\'e 

 bouquets of antlers (Wislocki et ah, 1947). An axis deer which was 

 observed for 5 years following castration (Bullier, 1948) exhibited 

 increasingly abnormal antler morphology as frozen tines were lost 

 and regrown. These and other species of deer tend also to develop 

 unusually thickened bases, from which varying numbers of tuberosi- 

 ties may grow. Excessive thickening of antler branches may lead to 

 the production of "cactus bucks," as described b\- Mearns ( 1907 ) in 

 the mule deer {Odocoileus hemionus) . Most remarkable of all, how- 

 ever, are the tumorlike masses into which the antlers of castrated 

 roe bucks develop (Olt, 1927; Blauel, 1935, 1936; Bickel, 1936; 

 Kleesiek, 1953). These amorphous outgrowths, known as peruke 

 antlers, may grow down over the animal's head like a wig, obstruct- 

 ing the vision and ultimately resulting in death from necrosis and 

 infections. Such abnormalities may be attributed in part to incom- 

 plete ossification in the absence of adequate amounts of testosterone. 

 The pronghorn antelope, incidentally, responds to castration in a 

 comparable manner by failing to shed the horn sheaths. Thus the 

 successive annual increments of horn remain attached seriatim in 

 an' abnormally curved accumulation of sheaths (Pocock, 1905). 



In contrast to the dramatic effects of castration on deer of the 

 usual kinds, reindeer and caribou antlers appear to be considerably 

 less dependent on sex hormones, a condition probablv correlated 

 with the bisexual occurrence of antlers in these animals. As in other 

 kinds of deer, castration of males after the velvet has peeled elf 

 results in shedding of antlers in 2 to 3 weeks (Hadwen and Palmer, 

 1922). Males castrated while their antlers are in velvet, however, 

 retain their antlers in this condition until spring, when the skin is 

 lost and the antlers are shed (Tandler, 1910; Tandler and Grosz, 

 1913; Hadwen and Palmer, 1922; Fisher, 1939). Antlers are grown 

 annually thereafter, although they are heavier, less calcified, and 

 permanently in velvet, and are shed later than normal. Tandler and 

 Grosz (1913) reported that a spayed female reindeer reacted in this 

 same manner. These deer are thus capable of annual renewal of 

 antlers even in the absence of gonads, but how the velvet can be 

 lost in the presumed absence of testosterone remains to be ex- 



