of skull length relative to the large known adult individuals. The study's results likewise indicate that there is a dissociation between body size and cranial development in tyrannosaurs, while simultaneously allowing better identification of juvenile remains that may have been misidentified in museum fossil collections. It is estimated that an ontogenetic dietary shift of Gorgosaurus and Albertosaurus occurs when the mandibular length reaches , indicating that this is the stage when their bite force increases exponentially and when they begin to pursuit large prey. Paleopathology Several pathologies have been documented in the Gorgosaurus libratus holotype, NMC 2120. These include the third right dorsal rib, as well as healed fractures on the 13th and 14th gastralia and left fibula. Its fourth left metatarsal bore roughened exostoses both in the middle and at the far end. The third phalanx of the third right toe is deformed, as the claw on that digit has been described as "quite small and amorphous". The three pathologies may have been received in a single encounter with another dinosaur. Another specimen cataloged as TMP94.12.602 bears multiple pathologies. A longitudinal fracture is present in the middle of the right fibula's shaft. Multiple ribs bear healed fractures and the specimen had a pseudoarthortic gastralium. Lesions from a bite received to the face were present and showed evidence that the wounds were healing before the animal died. TMP91.36.500 is another Gorgosaurus with preserved face bite injuries but also has a thoroughly healed fracture in the right fibula. Also present was a healed fracture in the dentary and what the authors describing the specimen referred to as "a mushroom-like hyperostosis of a right pedal phalanx." Ralph Molnar has speculated that this may be the same kind of pathology afflicting an unidentified ornithomimid discovered with a similar mushroom shaped growth on a toe bone. TMP91.36.500 is also preserved in a characteristic death pose. Another specimen has a poorly healed fracture of the right fibula, which left a large callus on the bone. In a 2001 study conducted by Bruce Rothschild and other paleontologists, 54 foot bones referred to Gorgosaurus were examined for signs of stress fracture, but none were found. Bite force Just like other tyrannosaurids, bite force of Gorgosaurus and Albertosaurus increases slowly among young individuals, and then it increases exponentially when they reach the late juvenile stage. In 2012, Jovannelly and Lane estimated that Gorgosaurus could exert a bite force