One of the debates that surfaces regularly in dinosaur science is how hard could Tyranosaurus rex (favorite dinosaur of small boys everywhere) actually bite. This has implications for the behavior of the living animal, as if it had a hard bite it would have been one of the most formidable predators ever, but if it had a week bite it was probably a scavenger. A similar debate runs with regard to T. rex's running speed; fast equals formidable predator, slow equals scavenger.
In a paper published in the journal Biology Letters on 29 February 2012, Karl Bates of the Department of Musculoskeletal Biology at the University of Liverpool and Peter Falkingham of the School of Earth, Atmospheric and Environmental Science at the University of Manchester, present a new computer simulation of the biting power of adult and juvenile T. rex's, based upon computer models calibrated by testing the computer estimates of the biting power of Human volunteers and Mississippi Crocodiles against the results obtained experimentally.
Three dimensional computer models of T. rex. (a) With soft tissue reconstructed (red, adductor mandibulae externus group; blue, adductor mandibulae posterior group; purple, pterygoideus group). (b) Model with joint centres (green circle), muscles (red cylinders), and ‘contact’ springs (blue spheres and cylinder) on the teeth in the initial simulation starting pose. (c) Model during sustained biting. Bates & Falkingham (2012).
Bates & Falkingham compared the calculated bite of juvenile and adult T. rex specimens to the known biting power of Humans and Mississippi Crocodiles and the calculated biting power of the Jurassic Therapod Allosaurus and concluded that the bite of the adult T. rex was considerably grater than would have been predicted from studying the juvenile, and consistent with the possibility that T. rex might have had the hardest bite of any terrestrial animal ever. They also compared the study to previous studies on T. rex and other large Theropods.
Comparison of the biting forces obtained from this study (white) with that obtained from earlier studies. A. Adult. J. Juvenile. Bates & Falkingham (2012).
One animal that seems to be notably absent from this study, and which in the past has been considered a contender for the hardest bite ever is the Cretaceous Giant Crocodile Sarcosuchus. In modern environments Crocodiles generally bite harder than mammals, so comparing T. rex to smaller crocodilians (the Mississippi Alligator is not even the largest extant crocodilian), smaller theropods, primates and a big cat (cats kill by squeezing the neck quite gently; the more tear-the-throat-out approach of Hyenas produces a far harder bite), does give T. rex a bit of an advantage in a hardest biter competition.