Antler Shedding in Relation to Parturition in Female Reindeer

Abstract

Observations were made on 4S individually recognized adult female reindeer ( Rangifer tarandus) as to exact date of parturition and antler shedding. Fifty percent of the cows had shed their antlers within 5 days postpartum. The maximum number of sheddings per day occurred on the sixth day after parturition. Postpartum retention of antlers varied from 1 to 11 days. No difference was found between old and young cows. The significance of antlers in female reindeer during calving season is discussed. It is supposed that possession of antlers gives the cow high social status which, combined with a high aggressive level, enables her to drive away other reindeer from the calving area, the calf thus being prevented from establishing contact with strange reindeer. It is supposed that the establishment of social mother-calf bonds would be impeded if strange reindeer were allowed to interfere. In a number of papers on reindeer and caribou (Rangifer tarandus) the shedding of antlers in females is discussed. Most authors agree that pregnant females retain their antlers until the calves are born, while barren cows cast their antlers 1-2 months earlier. There is, however, some disagreement as to the time interval between parturition and antler shedding. SemenovTyan-Shanskii ( 1948 ) reports that females drop their antlers within 3 days postpartum; Kuhmunen (unpublished data) found 24 days as the interval; Palmer (1934) gives 5-7 days; and Lent ( 1965 ), in his extensive studies on caribou, reported that no cows retained their antlers for more than 1 week after parturition. Except for Lent, the statements of the cited authors are not supported by any detailed evidence; however, Lent based his statement on several routine counts of cows with old antlers, and whether the cows were accompanied by calves. He apparently had no opportunity to relate parturition to antler shedding in 1 This work has been supported by the Swedish Natural Science Research Council. single animals because his whole study was on a population level.