CHANGES IN THE RELATIONSHIP BETWEEN PALMATE AND CERVINE ANTLERS IN MOOSE (ALCES ALCES) IN SOUTHEASTERN NORWAY

Abstract

Moose (Alces alces) have evolved 2 antler morphs; palmate and cervine. Using data from 1,186 antlers collected from moose harvested in southeastern Norway during 1950-1997, I rested the widely held hypothesis that the cervine morph has become the predominant antler type in Norway. The antlers were categorized according to palmate, intermediate, and cervine form. I also used quantitative measurement of tines (average length and number) to study trends in morphology. An adaptive landscape method was used to study a combination of the relative number of tines and relative tine length. Since 1950, the palmate morph decreased significantly by 0.52% per year (P = 0.002), while the cervine morph increased significantly by 0.39% per year (P = 0.008). Number of tines decreased in the palmate morph, but there was no trend in tine length. Th intermediate morph increased in the number of tines and decreased in tine length, while the cervine morph showed no trends in morphology. Combined for all morphs in the adaptive landscape, the relative number of tines decreased and relative tine length increased throughout the time series, indicating a change toward more cervine antlers in southeastern Norway. The causes for this change are discussed in relation to frequency-dependent selection and density/social stress hypotheses.