Now that we have a better picture of how typical flesh-eating dinosaurs’heads and necks were put together, Walking Dinosaur Costume we can figure out in more detail how they bit their victims. The Scurved neck was oriented toward vertical action, as was the deep, narrow skull. These long-limbed bipeds were tall animals that struck out and down at their victims, a very different system than that of lowslung lizards, who use their laterally flexible bodies and necks to strike sideways. Robert Bakker showed that since the lower teeth were smaller, more conical, and less curved than the upper ones’ they dug into and pinched out a fold of flesh while the bigger upper blades did the actual slicing and cutting. Animatronic Dinosaur This means that the skull had to slide backward relative to the mandibles. The sliding jaw joint allowed such a motion, and the pow0rful down-and-backward-running fibers of the pterygoideus muscles helped accomplish it. So did the high-powered neck muscles, which first helped drive the jaws forward into the prey, then pulled the upper jaw down and back to further lengthen and deepen the wound. Violently shaking the head back and forth would increase the damage.
With the exception of the posterior pterygoideus that loops around the underside of the mandible, the major jaw-working muscles were pretty much inside the skull. So, unlike mammals, but like reptiles and birds, theropods did not have many external facial or other outer skull muscles apartfrom thin bands of lip muscles, the eyelid muscles, and the depressor mandibulae at the back of the head. The latter helped open the jaws, something gravity alone cannot do as quickly because of the jaw-closing muscles. Realistic dinosaur costume As for the lip bands, these were like those of lizards, and were supplied with blood vessels and nerves via numerous small openings (foramina).e These lips could be lifted to bare the teeth in a threatening gesture, or lowered to help cover the teeth when the mouth was closed. Restorations that show theropods with naked croclike teeth are very much in error. But the tips of the teeth may have sometimes been exposed like some house gets’sspecially in the long-toothed forms like Dilophosourus, Tynannosourus rex, and young Albertosaurus libratus. The soft elastic skin that stretched between the backs of the upper and lower jaws and covered the jaw muscles was a related feature. Completely folded when the jaws were closed, it stretched out to a large sheet when they opened.