The biggest carnivorous dinosaur is Tyrannosaurus rex. It walks on two powerful legs. The head part consists of huge jaws with pointed, replaceable teeth and well-developed jaw muscles. It had tiny arms, each with two fingers. It ranges from 40 feet (12.4 m) long, about 15 to 20 feet (4.6 to 6 m) tall. It weighs up to 5 to 7 tons. Their eyeballs range about 3 inches. Its prey is plant-eating dinosaurs. They run up to 15 mph (24 kph). Their tooth is up to 9 inches. Tyrannosaurus rex fossils have been found in western North America and Mongolia. Tyrannosaurus rex is one of the largest terrestrial carnivores of all time.