It is 193 million years ago in the Early Jurassic Period, and the predatory dinosaur Dilophosaurus wetherilli is chasing the basal sauropodomorph Sarahsaurus aurifontanalis across the arid plains of southwestern North America. Although Dilophosaurus is often portrayed in popular culture as being able to spit venom, there is no evidence that it could do so, and it probably didn’t need that ability anyway as the apex predator in its habitat.