The Find

This T. rex was found in the badlands of eastern Montana by rancher Kathy Wankel. Kathy first spotted a small piece of the shoulder and arm weathering out of the ground. In 1990, paleontologist Jack Horner and a crew from the Museum of the Rockies carefully removed the overlying rock and excavated what turned out to be a nearly complete Tyrannosaurus rex. Only a small region of the tail was missing. Kathy’s discovery was truly a spectacular find. For the first time, the complete forearm of Tyrannosaurus was preserved, allowing estimates of its strength and function. The pictures next to the exhibit reveal how closely the bones were found together (articulated). When an animal dies, the tendons in the neck shrink and the head is often "pulled" backward toward the tail. Notice the skull lying over the hip region.

For further information, read The Complete T. rex by Jack Horner and Don Lessem.

The Mount

Each of the "bones" is a cast from the original skeleton. There are more than 300 bones and when the casts arrived, they were in a huge crate, unlabeled, with no instructions! The responsibility of designing and constructing the mount belonged to Principal Museum Scientist, Mark Goodwin. Mark assembled a talented crew of four to assist him in the four-month project. Each cast was hand-tooled, painted, drilled, and then placed over an internal steel armature designed to show the skeleton in a lifelike pose. Our T. rex is running at full speed, when suddenly it turns its head; maybe it’s dinner time!

The rex

You can print out this page and bring it with you to the Museum so you can follow along while viewing the skeleton. Looking at the skull, you will see that it has a high, broad face with strutlike bones framing large openings. This pattern is characteristic of carnivorous dinosaurs. Notice too that these bones are somewhat loosely fit together — there is some kinesis, or "give", possible between these bones when the animal bites down on its prey. This is important because it appears that T. rex had great power in its jaws. The teeth of most carnivorous dinosaurs are somewhat flattened side to side, like daggers. They are also curved and serrated like steak knives on their front and back edges. But in T. rex, the teeth are not flattened side to side, although still serrated. They are fatter, and their roots reach deep into the skull, so the whole shape is much like a banana. Think of a mouthful of lethal bananas!

Notice how enormous the skull and legs are. The animal had only to plant its feet and take a bite out of its prey to cause tremendous damage. The forelimbs are very small, for reasons that are not immediately obvious. But it seems that forelimbs were not necessary for this animal's way of life. From years of watching monster movies on TV, we might think that predators defend their territories against large rival males of other species. But the image of a big T. rex fighting a big male brontosaur or stegosaur to the death (besides being historically inaccurate) is quite different from what happens with today's predators. Sharks, lions, hyenas, and Komodo dragons all make their living by preying on the sick, injured, very old, or very young members of prey species. They tend not to wrestle healthy animals to the death, but to dart in and inflict an injury, then retreat and watch the weakened prey until they can strike again or the animal collapses. It is likely that T. rex and other dinosaurian predators did the same. Like many predators, they were probably not above scavenging fresh meat either.

We think of T. rex as being so large that it may not have moved quickly, but it certainly seemed capable of getting up to speed in Jurassic Park! Recently, however, scientists studied the film to estimate the speed at T. rex was moving. They calculated that it "maxed out" at ten to twelve miles per hour in the film — certainly not enough to catch a fleeing Land Rover! But footprints of large carnivorous dinosaurs suggest speeds of 20 mph or more, at least for short stretches. T. rex was one of the last dinosaurs we find at the end of the "Age of Dinosaurs" (along with Triceratops). It was one of the largest known land carnivores of all time. We aren’t sure why T. rex became extinct, but we can wonder at its existence.

The T. rex skeleton is located on the ground floor of the Valley Life Sciences Building in the circular stairwell. You get a chance to walk up and around the largest land carnivore to have ever roamed the planet! Stop by for a look. To learn more about Tyrannosaurus rex, see the T. rex exhibit. Or to learn more about other dinosaurs, see our Dinosaur exhibit.

Directions and times for the Valley Life Sciences Building (VLSB).