Canine tooth strength and killing behaviour in large carnivores

Abstract

Bending strength of upper canine teeth is examined among living canids, felids, hyaenids and several extinct species including sabretooth cats, borophagine dogs and the dire wolf, Canis dirus. The tooth is modelled as a cantilever with an elliptical cross‐section. Using beam theory, the bending strength of the upper canine is calculated given a constant force applied to the canine tip. Results indicate that felids and hyaenids have relatively stronger canines than canids, particularly in bending about the anteroposterior (AP) rather than the mediolateral axis. It is suggested that canine shape reflects the forces produced during killing and feeding. As shown by an analysis of jaw muscle moment arms, felids and hyaenids have relatively stronger bites than canids. Moreover, the canines of hyaenids and felids are perhaps more likely to contact bone during feeding and killing and consequently may be subjected to larger and more frequent bending moments about the AP axis. The canines of sabretooth cats are shown to be more similar in shape and strength characteristics to those of living canids than felids, whereas those of the borophagine dogs and the dire wolf are closer to modern hyaenas.

Claw morphometrics in monitor lizards: Variable substrate and habitat use correlate to shape diversity within a predator guild

“…Claws built for puncturing wood would benefit from a very narrow tip (Cartmill, 1985), whereas burrowers may benefit from a wide claw as it would help transport soil (Hildebrand, 1985). Excluding the third dimension also prohibits investigating certain biomechanical principles by assessing lateral bending strengths (performed for teeth by Valkenburgh and Ruff (1987)), or conducting finite element modelling (Lautenschlager, 2014; Manning et al., 2009). Future studies should consider in what way medial‐lateral claw characters may influence claw function.…”

Incisor Crown Bending Strength Correlates With Diet and Incisor Curvature in Anthropoid Primates

“…Biknevicus et al (1996) modeled carnivore incisors as a cantilever beam and determined that incisor bending strength is largely a function of cross-sectional geometry. Any increase in the maximum LL and MD dimensions of the incisor crown results in a proportionate increase in bending strength (van Valkenburgh and Ruff, 1987;Plavcan and Ruff, 2008). Given that an increase in anthropoid MD and CI crown curvature would effectively increase labiolingual crown dimensions, it stands to reason that incisors with increased crown curvature will be more resistant to bending stresses.…”

“…Figure 2 illustrates the linear dimensions used in the present study. Van Valkenburgh and Ruff (1987) have previously demonstrated that teeth with relatively simple crown morphology (i.e. unicuspid incisors and canines) can be modeled as a cantilevered beam that is rigidly fixed at one end to the bone of the maxilla or mandible, although such a model does not consider more nuanced aspects of incisor morphology (i.e.…”

The effects of gape angle and bite point on bite force in bats

“…If equal forces were generated in both unilateral and bilateral canine biting, the canine teeth involved in unilateral biting would experience much higher concentrations of stress. In contrast to the canines of carnivorans, the canine teeth of bats are relatively long, thin and exhibit sharp crests along their length (Freeman, 1992 ability of these teeth to initiate and propagate cracks in food items (Freeman, 1992), it is not well suited to resist breaking under high loads (Van Valkenburgh and Ruff, 1987). Given the shape of bat canine teeth and the concentration of forces on fewer teeth during unilateral biting, we suggest that sensory feedback from the canine alveoli may serve as a signal to decrease bite force during unilateral canine biting and thus protect these teeth from high stresses and potential damage.…”