Meeting Abstract
Tusks are mostly seen on smaller ungulates and used primarily as sexual weapons, whereas larger ungulates lack tusks but instead possess antlers, used as a visual display of social status. There are two Genera of deer that have both antlers and tusks: Muntiacus and Elaphodus. In muntjacs, all fights are preceded by a “dominance display”, typically performed by the dominant male, resulting with the subordinate male’s withdrawal. A gradual increase in the influence of this display may have led to the reduction in size of tusks and eventual evolution of complex, large antlers due to the rarity of fighting. The current project will study the correlation between antlers and tusks in relation to overall body size and other ecological factors. We hypothesize that as body size increases, relative size of tusks will decrease and the relative length of antlers will increase. Antler and tusk data on several species of cervids have been collected from the museum specimens. We will use this data to determine the correlation by using phylogenetic generalized least squares tests, which are regression type tests that take species relatedness into account. Our preliminary studies suggest that as the species move from closed to open habitats, from solitary to group living lifestyles, and from small to large body sizes there is a significant trend of decrease in tusk size and increase in antler size. We propose to examine the effects of environmental and social factors, such as habitat type and fighting style, on the evolution of these traits. The significance of the question is that it would help contribute to our understanding of the selective forces that led to the transition between small solitary tusked deer and large social/polygynous antlered deer.
