The structure of the mandibular corpus and its relationship to feeding behaviours in extant carnivorans

Abstract

Assuming some optimization of bone structure to applied mechanical loadings in vivo, different killing and feeding behaviours in carnivores should be reflected in observed differences in cross‐sectional shape of their mandibular corpora. Section moduli are used to gauge the magnitudes of bending moments in the mandibular corpus and, when dentary length is controlled, the magnitudes of forces applied to the corpus. Comparisons are made of section moduli at the P3P4 and P4M1 interdental gaps among canids, felids and hyaenids; in canids only, the M1M2 interdental gap was also studied. Local variations in loadings are identified by comparing the section moduli at adjacent loci along the corpus within each family. The findings of this study show that the precarnassial corpora of canids and hyaenids have greater strength in bending than the corpora of felids of similar body weight. This is taken to reflect relatively greater bending moments under loading in the corpora of canids and hyaenids due, in part, to their elongate dentaries (relative to body weight). Relative to dentary length, however, the precarnassial corpora of felids and hyaenids have much greater strength in bending than the corpora of canids. These scaling relationships appear to reflect the high customary forces (i.e. not moments) applied to the precarnassial corpora of felids and hyaenids with sustained canine killing bites and with bone ingestion using the premolars, respectively. An increase in bending strength of the corpus caudal to the camassial blade in canids is interpreted to be an adaptation for bone‐crushing with the postcarnassial molars.

Go big or go fish: morphological specializations in carnivorous bats

“…Conversely, vertebrates have highly elastic and pliant skin and muscles covering a stiff, tough and usually mineralized skeleton [6]. Since mammals kill and masticate prey before ingestion, the differences in structure and physical properties of insect and vertebrate prey probably present different selective pressures on the morphology of the feeding apparatus of insectivorous versus carnivorous species [7][8][9][10]. Carnivores exhibit cranial and dental morphologies that are specialized for processing muscle and-sometimes-bone, in addition to being suited to capture and kill vertebrate prey [8,9,11].…”

A Preliminary Analysis of Correlations between Chewing Motor Patterns and Mandibular Morphology across Mammals

“…Morphologists have put forth significant effort describing patterns of evolutionary variation in the bones, muscles, and teeth of the mammalian masticatory apparatus (e.g., Gregory 1922;DuBrul and Sicher 1954;Maynard Smith and Savage 1959;Turnbull 1970;Scapino 1972Scapino , 1981Hershkovitz 1977;Hylander 1979a;Lucas 1979;Radinsky 1981Radinsky , 1985Greaves 1982;Freeman 1988;Ravosa 1991;Biknevicius and Ruff 1992). Compared to these morphological descriptions, we know far less about variation across mammals in physiological measures during feeding, such as jaw-muscle activity, jaw movements, and tissue deformations.…”

Phylogenetic, behavioral, and dietary constraints on felid masticatory morphology /

“…The emphasis on the hinge-like motion of the felid mandible in descriptions of carnivoran jaw mechanics (e.g., Smith & Savage, 1959;Becht, 1954) obscures the fact that movement at the TMJ is quite complex, with rotation and translation occurring about three axes (Gorniak & Gans, 1980 (Smith & Savage, 1959) or effecting simultaneous occlusion of the dentition (Davis, 1964 (Greaves, 1974 (Radinsky, 1981a;Biknevicius & Ruff, 1992). example (Radinsky, 1981a;Van Valkenburgh & Ruff, 1987).…”