HYENA SKULL


Hyenas possess the strongest jaw muscles among terrestrial mammals. This fact is reflected in their skull morphology. Hyenas have a prominent fossa (depression) along the rami of the mandible (posterior vertically oriented portion that articulates with the cranium). The rami (singular=ramus) are also much thicker and longer than that of most vertebrates. Hyenas also have a strongly convex zygomatic arch beneath the eye orbit. These features contribute to accomodating a massive masseter (jaw adductor) muscle with a firm attachment surface. Another adaptation for stronger jaw musculature is a prominent mid-sagittal crest that runs along the top of the skull. This allows for more firm attachment of additional jaw musculature such as the temporalis. The length and height of the crest allows for greater leverage, greater attachment surface, and larger numbers of angles to which the muscles may orient. The eyes tend to be more forward in their orientation, typical of many predators. This allows greater stereoscopic vision and depth perception. All of these features reflect a predatory lifestyle and an ability to crush bone and produce a vise-like grip on their prey.