Maximum Bite Force and Prey Size of Tyrannosaurus rex and Their Relationships to the Inference of Feeding Behavior

Historical Biology (Impact Factor: 1.49). 07/2003; 16(1):1-12. DOI: 10.1080/0891296021000050755


The feeding behavior of the theropod dinosaur Tyrannosaurus rex is investigated through analysis of two variables that are critical to successful predation, bite force and prey body mass, as they scale with the size of the predator. These size-related variables have important deterministic effects on the predator's feeding strategy, through their effects on lethal capacity and choice of prey. Bite force data compiled for extant predators (crocodylians, carnivorans, chelonians and squamates) are used to establish a relationship between bite force and body mass among extant predators. These data are used to estimate the maximum potential bite force of T. rex, which is between about 183,000 and 235,000 N for a bilateral bite. The relationship between maximum prey body mass and predator body mass among the same living vertebrates is used to infer the likely maximum size of prey taken by T. rex in the Late Cretaceous. This makes it possible to arrive at a more rigorous assessment of the role of T. rex as an active predator and/or scavenger than has hitherto been possible. The results of this analysis show that adult Triceratops horridus fall well within the size range of potential prey that are predicted to be available to a solitary, predaceous T. rex. This analysis establishes boundary conditions for possible predator/prey relationships among other dinosaurs, as well as between these two taxa.

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    • "Tyrannosaurids employed several specializations for hunting and feeding that distinguish them from other theropod dinosaurs. Adults imparted high bite forces that enabled the crushing and splintering of bone (Erickson & Olsen, 1996; Erickson et al., 1996; Meers, 2003; Wegweiser, Breithaupt & Chapman, 2004; Therrien et al., 2005; Happ, 2008), and their skulls possessed structural modifications for withstanding complex reaction forces (Holtz, 2002; Hurum & Sabath, 2003; Rayfield, 2004; Therrien et al., 2005; Snively et al., 2006). Postcranial morphology suggests modes of intercepting prey. "
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    ABSTRACT: Tyrannosaurid necks were strong and powerful instruments for wielding the jaws during feeding. Hypotheses of tyrannosaurid neck function are here grounded by observations of neck morphology and function in extant archosaurs. Respectively derived morphologies in birds, crocodilians and tyrannosaurids compromise inferences for some muscles. However, alternate reconstructions indicate that tyrannosaurid neck muscles combined the robustness of crocodilian musculature with the functional regionalization seen in birds. Alternate hypothesized attachments of an avian-style muscle, the M. complexus, indicate different capacities for head dorsiflexion and lateroflexion. Electromyography of the M. complexus in chickens strengthens inferences about its function in both dorsiflexion and lateroflexion in extinct dinosaurs, and further suggests that it imparted roll about the longitudinal axis in concert with the actions of contralateral ventroflexors. Videography of extant raptors reveals the involvement of the neck when striking at prey and tearing flesh, and reconstructed tyrannosaurid musculature indicates capacity for similar neck function during the feeding cycle. As for birds, muscles originating in the anterior region of the neck likely stabilized the head by isometric or eccentric contraction as tyrannosaurids (and other large theropods) tore flesh by rearing back the body through extension of their hind limbs.
    Journal of Zoology 04/2014; 292(4). DOI:10.1111/jzo.12109 · 1.88 Impact Factor
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    • "The complete skull of Josephoartigasia monesi provides a foundation to study the bite mechanics of this species. The bite force is an important aspect of mammal ecology and shed light into the palaeobiology and ecological role of some species (Christiansen & Wroe 2007; Meers 2002; Therrien 2005a,b; Vizcaíno & De Iuliis 2003; Wroe et al. 2005). "
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    ABSTRACT: Blanco R.E., Rinderknecht, A. & Lecuona, G. 2011: The bite force of the largest fossil rodent (Hystricognathi, Caviomorpha, Dinomyidae). Lethaia, Vol. 45, pp. 157–163. An exceptionally well-preserved skull of the largest fossil rodent Josephoartigasia monesi allows the first analysis of the bite mechanics of this group of South American giant rodents. In this study, we reconstructed the main anatomical features of the skull of this Pliocene rodent, relating them to the bite force at incisors. Bite force was estimated using three different techniques. Two methods suggest that bite forces at incisors of around 1000 N were possible for these mammals. However, the incisors seem to be stronger than expected for this bite force implying that the bite forces may have been greater than 3000 N. We consider three hypotheses: allometric effects, teeth digging or defence against predators, to explain our results. □Bite force, Dinomyidae, incisors, largest rodent, Pliocene.
    Lethaia 04/2012; 45(2). DOI:10.1111/j.1502-3931.2011.00265.x · 1.45 Impact Factor
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    • "The maximum prey size that can be taken by a predator is strongly influenced by biomechanical limitations. Skull shape and bite force adjusted for body mass correlate with prey size and feeding ecology in many terrestrial carnivores (Meers, 2002; Wroe et al., 2005; McHenry et al., 2006; Wroe & Milne, 2007). Different cranial shapes among extant dasyuromorphians have been correlated with diet (Wroe & Milne, 2007), and yet little is known about how the biomechanical performance of these structures may reflect dietary functions. "
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    ABSTRACT: Extinction risk varies across species and is influenced by key ecological parameters, such as diet specialization. For predictive conservation science to be effective, we need to understand extinction risk factors that may have implicated recent species extinctions. Diet and feeding behaviour of the large extinct marsupial carnivore Thylacinus cynocephalus or thylacine have long been debated. Improved understanding of the skull's biomechanical performance and its limitations in a comparative context may yield important insights. Here, we use three‐dimensional (3D) finite element analysis to assess aspects of biomechanical performance in the skull of T. cynocephalus relative to those of two extant marsupial carnivores with known diets that occurred sympatrically with T. cynocephalus: the Tasmanian devil, Sarcophilus harrisii, and spotted‐tailed quoll, Dasyurus maculatus. Together, these three species comprised the large mammalian carnivore guild in Tasmania at the time of European settlement. The bone‐cracking S. harrisii produced high bite forces for its size as expected, but the stresses induced were surprisingly high. A higher proportion of cancellous bone in the skull of this osteophage may act to absorb shock but decrease rigidity and hence raise stress. A relatively high bite force and rigid skull characterized D. maculatus, which may allow them to target prey of variable sizes. Compared with S. harrisii and D. maculatus, we found that the skull of T. cynocephalus was least well adapted to withstand forces driven solely by its jaw‐closing musculature, as well as to simulations of struggling prey. Our findings suggest that T. cynocephalus likely consumed smaller prey relative to its size, which may have had implications for their survival.
    Journal of Zoology 12/2011; 285(4-4):292-300. DOI:10.1111/j.1469-7998.2011.00844.x · 1.88 Impact Factor
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