Tyrannosaurus rex could chomp down with enough force to crush a car. Now, researchers know just how the dino did it, National Geographic reports. Scientists long thought T. rex’s skull might be similar to those of its modern-day reptile and bird relatives, many of which have flexible skulls with movable bones on the top of the mouth, known as palates. To test the theory, researchers created models of how bite force might have affected bones in the lizard king’s skull, depending on its formation. A geckolike skull, for example, gave the T. rex palates that could flex out to the sides, and a more parrot-esque version let the bones move up and down. After analyzing several models, the researchers concluded that the only way for T. rex to have such a ferocious bite was to have a stiff, nonflexible noggin, they report this month in The Anatomical Record.