Tyrannosaurus rex was one of the most ferocious predators to ever walk the Earth. With a massive body, sharp teeth, and jaws so powerful they could crush a car, the T. rex dominated valleys in western North America, 68 million years ago.
Tyrannosaurus rex, whose name means “king of the tyrant lizards,” was built to rule. This dinosaur’s muscular body stretched as long as 40 feet—about the size of a school bus—from its snout to the tip of its powerful tail. Weighing up to eight tons, T. rex stomped headfirst across its territory on two strong legs. These dinosaurs preyed on living animals and scavenged carcasses—and sometimes they even ate one another.
The head of a T. rex was the real stuff of nightmares. This fierce carnivore was optimally built for crunching through its meals, with a stiff skull that allowed it to channel all the force of its muscles into one bite—delivering up to six tons of pressure. This dinosaur used its 60 serrated teeth, each about eight inches long, to pierce and grip flesh, throwing prey into the air and swallowing it whole. To keep itself from overheating while crushing prey with its mighty jaws, the giant animal had vents in its head to help its brain stay cool, similar to those found in alligators.
Tyrannosaurus rex was also adept at finding its prey thanks to a keen sense of smell. T. rex had almost as many genes encoding its olfactory receptors as a house cat does today. This powerful snout also likely helped T. rex find mates and detect other predators.
Not everything about Tyrannosaurus rex was fierce, however. This dinosaur had unexpectedly puny arms. The function of these little limbs is a source of debate among scientists. Some believe T. rex’s arms were adapted for vicious slashing at close quarters, given their ability to inflict deep wounds with four-inch claws.
And while they had strong thighs, these dinosaurs were not speedy. They could only walk briskly at up to 12 miles an hour—likely not fast enough to chase a speeding Jeep, as depicted in the movie Jurassic Park. Using biomechanical models, scientists have theorized that if these heavy animals moved any faster, they would have shattered the bones in their feet.
See also: Jurassic Dinosaur Family.