Meeting Abstract

P3.58  Saturday, Jan. 5  Maximum running speed in mammals is inversely correlated with a proxy for male-male competition. CARRIER, David/R; Univ. of Utah carrier@biology.utah.edu

The physical demands of rapid and economical locomotion differ from the demands of aggressive behavior in ways that may prevent simultaneous evolution of optimal performance in both behaviors. In this analysis, I used body size sexual dimorphism as a proxy for species levels of male-male aggression to test the hypothesis that species of mammals that are specialized for aggressive behavior tend to be slow runners. Species values of male and female body mass, and maximum running speed were collected from the literature. The scaling effects of body mass on size sexual dimorphism and maximum running speed were removed by calculating body mass residuals. Regression of body mass residuals of maximum running speed against size sexual dimorphism for 28 species that inhabit open habitats demonstrated a significant negative correlation (r2 = 0.468, P-value < 0.0001). Hence, species of mammals that have relatively high levels of size sexual dimorphism tend to be slow runners. This observation is consistent with the hypothesis that specialization for aggressive behavior is incompatible with simultaneous specialization for high-speed running.