Comparative Functional Anatomy of the Oral Jaw Musculo-skeletal System in Pacific Salmons

Abstract

Food acquisition is a necessary component of survival for any organism and in order to feed effectively, a predator must meet the mechanical demands of its prey. This study’s focus was to make general observations and conclusions about the evolution and adaptation of several morphological traits of pacific salmon jaws based on varied feeding behaviors. Dissections of juvenile king, adult king, and keta salmon were performed, during which measurements pertaining to the articular joint and adductor mandibulae were taken and recorded. The study found that king salmon have stronger adductor mandibulae, while keta have stronger skeletal jaw components. This trade-off is a morphological adaptation in which either force or velocity can be prioritized. Each species’ jaw anatomy is specialized for their diet and feeding habits, for example stronger jaws to accommodate the crushing of tough prey or fast jaw closure for hunting fish prey. Other conclusions, like the positive correlation between head length and adductor mandibulae mass, were also drawn from the study.