Meeting Abstract
The majority of mammals use biting to ingest prey. Therefore, determining how bite force varies across species is an interesting problem in light of the great ecological and dietary diversity of mammals. Here, we examined bite force in a diverse carnivoran clade, the Musteloidea (weasels, otters, raccoons, and skunks). Musteloids are a tractable group for morphological studies because there is a well resolved time-calibrated phylogeny, musteloid specimens are nicely represented in museums, and, despite their carnivoran habits, many musteloids have evolved diets that vary in the percentage of meat consumed. In addition to hypercanivorous habits, musteloids have evolved mesocarnivores, hypocarnivores, and even herbivorous and durophagous habits. Therefore, we asked whether diet evolution shaped the evolution of bite force in musteloids. We first examined the evolution of diet in musteloids using stochastic character mapping in the program SIMMAP. We find that hypocarnivory is the ancestral diet for musteloids and hypercarnivory solely evolved in the clade Mustelidae. Herbivory, however, evolved three independent times in the red panda, kinkajou, and olingos. We then estimated bite forces in 66 species of adult female musteloids using Thompson’s dry skull method and conducted macroevolutionary analyses to examine how diet affects the evolutionary scaling pattern between bite force and cranial size. We found that the evolution of bite force is isometric with respect to the geometric mean of head size across all of Musteloidea. We also discovered that the bite forces of herbivorous species and hypercarnivorous species scaled with positive allometry whereas bite forces of the remaining dietary categories scaled with isometry.
