Meeting Abstract
Temporalis muscle size is influenced by diet and method of food processing in terrestrial mammals. The correlation between the size of this muscle and feeding behaviors in whales has yet to be tested. The purpose of this study was to quantify the size of the area of attachment on the skull for the temporalis muscle, a proxy for the size of the muscle, for 209 specimens of 72 odontocete whales. The temporal fossa area was calculated using measurements of the temporal fossa height and width, with body size removed by dividing each measurement by the occipital condyle breadth, a correlate for body size. We used ANOVA statistical tests to determine if differences in temporal fossa area were present, and if they relate to diet (generalists vs fish vs squid, vs higher vertebrates dominant diets) and prey capture and processing strategy (suction vs snap vs ram vs. grip-and-tear feeding styles). Significant differences in the temporal fossa area were found between all feeding strategies except between grip-and-tear verses snap feeding. Grip-and-tear feeders along with snap feeders encounter a substantial amount of strain while feeding and would need a larger temporalis muscle to accommodate the higher bite force needed for their feeding style. Whales using the grip-and-tear feeding method had the largest temporal fossa area followed by snap feeding, ram feeding and suction feeding. The only significant differences in temporal fossa area in relation to diet were differences between consumers of bird and marine mammals versus those which fed on fish or squid. This study provides evidence that the temporal fossa of extant whales strongly associated with prey capture strategies and can be used as a tool to examine the feeding behaviors of fossil whales.
