DECIDUOUS NATURE OF DE?:R ANTLERS .'Ul 



events, namely, hardening of the bone, vascular constriction, and 

 shedding of the velvet. These events are set in train by increased 

 testosterone secretion, which also brings about the period of rut 

 following antler death. From this time on there exists, perforce, a 

 union between the compact dead bone of the antler base and the 

 live bony trabeculae of the pedicle. The line of demarcation is at 

 first usually convex, with respect to the pedicle, as is illustrated by 

 the concave base of an antler caused, by castration, to be shed in 

 the early autumn (Fig. 10). During the intervening months the 

 antler apparently dies back gradually, for when shedding occurs in 

 the spring, either naturally or because of castration, its base tends 

 to be convex (Figs. 11 and 12). In either case, the breakage plane 

 is characterized by numerous small bony spicules which are re- 

 sponsible for the rough texture of the antler base ( Fig. 8 ) . This base 

 is also remarkable for the normal absence of any traces of blood, a 

 fact indicating that it is the dead, not the living, bone that is eroded 

 prior to shedding. 



In 1859-1861, Wyman described the absorption of bone from 

 around the haversian canals just below the "burr," until each cavity 

 united with adjacent ones to effect a separation of the antler from 

 the pedicle. Amplified by the subsequent investigations of Lieber- 

 Kiihn (1861), Kolliker (1873), Caton (1875), Macewen (1920), 

 Gruber (1937, 1952^, 1952Z>), Wislocki (1942), and Waldo and 

 Wislocki (1951), Wyman's original account still represents an ac- 

 curate description of the basic process of antler shedding. Kolliker 

 (1873) emphasized that the events preceding shedding involve 

 hyperemia in the frontal pedicle and resorption of haversian la- 

 mellae in the central and peripheral regions of the antler-pedicle 

 junction. Thus, in its final days the antler remains attached only by 

 osseous trabeculae in a circular, intermediate zone, a fact that can 

 be verified by close examination of an antler base after shedding 

 (Fig. 8). 



In his investigations of roe deer and fallow deer, Gruber ( 1937, 

 1952a, 1952&) described and illustrated the numerous osteoclasts 

 so conspicuously arranged along the trabeculae of the distal end of 

 the pedicle. Under their influence, the bone is eroded and the inter- 

 trabecular spaces are correspondingly enlarged to accommodate 



