In a new scientific paper, researchers from Northern Illinois University and the Burpee Museum of Natural History in Rockford, Ill., report that adolescent tyrannosaurs got into some serious scraps with their peers. The evidence can be found on Jane, the museum's prized juvenile Tyrannosaurus rex. Jane's fossils show that she sustained a serious bite that punctured through the bone of the dinosaur's upper maxilla, the researchers report. In this photo of the upper left maxilla of Jane, three of four elliptical-shaped puncture wounds are evident. The researchers determined that another juvenile tyrannosaur was responsible for the injury.