An Investigation into the killing bite of Homotherium Serum
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Felidae, the family to which all living cats belong, is highly morphologically and behaviorally conserved. As a result, one can make inferences about extinct species, based on observations of living taxa. To investigate the predatory behavior of saber-toothed cats, I examined the killing bite of Homotherium serum, basing my work on the observations that modern large cats can kill with a non-penetrative compressive bite to the throat. This was done with three sets of experiments, each addressing different facets of the form/function relationship of the felid masticatory system. First, using replica jaws representing each of the three felid canine tooth types (dirk, scimitar, and conical), I applied static compressive bites to fresh animals. Water and air were pushed through the brain-bound arteries and each set of jaws was tested for its ability to cease flow, penetrate skin, and sever blood vessels. When biting thin-skinned prey, all cats demonstrated the ability to abolish flow with modest force and lower than maximum gape. Penetration was achieved with both sabertooths, but thick-skinned prey presented a greater challenge, and no internal vascular damage resulted. Next, I examined a tiger (Panthera tigris) and a caracal (Caracal caracal) through dissection and diffusible iodine-based contrast-enhanced computed tomography (diceCT), with the goal of more fully understanding the homology among cats regarding their masticatory anatomy, and to help develop more faithful virtual reconstructions of a lion (Panthera leo) and H. serum. Data from this analysis demonstrated a strong homology between two cats of considerable size difference, P. tigris and C. caracal. Muscular subdivision, fiber direction, and attachment sites were strikingly similar despite the difference in scale, and demonstrated a complex system of interconnected muscular units. Lastly, digital models, prepared according to anatomical analysis, were employed in Finite Element Analysis, with the goals of observing the behavior of the skulls of a P. leo and H. serum under loading conditions simulating a static, bilateral compressive bite, and to determine if preparing and utilizing models of greater muscular complexity would alter results. It was revealed that in attachment surface area and fiber direction has little impact on force generation or mechanical in the absence of realistic muscle properties. Ultimately the focus on minimizing bite force for effective kills conflicted with FEA experiments seeking to calculate maximum force generation. The differences between species in regards to these variables raised questions as to the utility of FEA in exploring killing bites as opposed to mastication for food processing. Nonetheless, it was demonstrated that sabertooths, similar to their modern counterparts, were capable of efficient, bloodless, compressive killing techniques.