An ethological analysis of the use of antlers as social organs by rutting bull moose (Alces alces gigas Miller)

Abstract

The behavior of rutting bull moose (Alces alces gigas) and their use of antlers as social organs was studied in Mt. McKinley National Park, Alaska during the autumns of 1977 and 1978. Bulls were placed into six antler-size classes. Expressive behavior was classified into the following categories: threat display, dominance display, submissive display, space claim display, excitement activity, and behavior that advertises presence and readiness to interact. Rates of bush thrashing, addressing threat and dominance displays, and frequency of bull associations with cows were all positively correlated with antler-size class. Expressive behavior of bull moose is centered on the antlers. Palmicorn antlers maximize visual effectiveness as social organs. It is concluded that moose antlers are important social organs. It is hypothesized that palmicorn antlers evolved as long-distance social organs.