A photograph of the Dunkleosteus terrelli fossil skull upon which this study was based. Scientists created a biomechanical model to simulate the jaw's function. From that they determined muscle mass and bite force. This ancient fish had a bite that exerted 11,000 pounds of force, the strongest bite of any fish ever, and one of the strongest bites of any animal, rivaling the bite of large alligators and Tyrannosaurus rex. The bladed dentition focused the bite force into a small area, the fang tip, at an incredible force of 80,000 pounds per square inch.