3-18 R. J. GOSS 



(1888-1891), Lvdekker (1898), and Brander (1923). In Ceylon, 

 Phillips (1927-1928) has recorded that these deer also exhibit ir- 

 regular antler cycles, but that in Southern and Uva provinces 75 

 per cent of them shed their antlers in April and May. Where the 

 shedding dates are not seasonally synchronized, the other aspects 

 of the antler cycle, as well as the period of rut and birth, are 

 similarly irregular (cf. Zuckerman, 1953). Yet despite the lack of 

 uniformity^ within a tropical population, there is a strong tendency 

 for individuals to grow successive sets of antlers at approximately 

 12-month intervals. According to the studies of Valera (1955) on 

 the Philippine deer ( Riisa sp. ) , antler shedding by different individ- 

 uals has been observed at a wide variety of times of year. It is note- 

 worthy that these males nevertheless adhered to annual antler 

 cycles, while the does underwent repeated estrus, sometimes as 

 frequently as every 15 days. In agreement with this is the informa- 

 tion generously supplied to the author by Sr. Tomas Blohm ( 1962- 

 1963) of Caracas, Venezuela, whose careful records of the antler 

 growth cycle in a captive Venezuelan deer indicate that antlers are 

 normally replaced at yearly intervals. In this particular specimen 

 {Odocoileus gijmnotis), successive sets of antlers were shed on De- 

 cember 8, 1958, December 1, 1959, December 19, 1960, and January 

 24, 1962. (Velvet was rubbed off in March or April of each year.) 

 The most recent shedding, however, occurred precociously on July 

 29, 1962, apparently induced by disease (gastroenteritis). Despite 

 this irregularity, the deer did not start to grow new antlers until its 

 usual time of vear in December. It then shed the velvet in April 

 1963, indicating that the basic annual rhythm had not been dis- 

 turbed. 



In temperate species of deer the breeding period is seasonally 

 controlled and coincides in the male with the maturation of the 

 antlers, an occurrence involving the shedding of the velvet, which 

 is induced by the increased secretion of testosterone characteristic 

 of the onset of rut. Should a similar situation prevail among tropical 

 deer, the polyestrous female could mate with only that fraction of 

 the available male population bearing mature antlers. That this is 

 not the case, however, is indicated by Mohr's ( 1932 ) account of the 

 hog deer (Hyelaphus porcinus) in the Hamburg Zoo: "At first sight 



