After the Wankel T.rexwas discovered, paleontologist Kenneth Carpenter and Matt Smith embarked on an intense and careful study and recreation of the T.rex forearm. Only the claws are missing from the Wankel T.rex arm, all other bones are intact from shoulder to fingers. The arm of T.rex is only about the size of an adult human arm (about 3 feet)—pretty small for an animal that can reach 40 feet in length! The bones may be short, but they are stout, which indicates strength. Based on the muscle scars the scientists were able to reconstruct the muscle tissue for the arm and establish where it attached to the bone. The bicep muscle attaches further down the forearm on a T.rex than on a human arm. This gives the T.rex less range of motion, but much greater leverage. Based on the elbow, scientists don’t think T.rex could extend its arm much past a 90° angle. T.rex could still move its arms front to back, and had limited motion laterally. The lower muscle attachment also means a great deal of strength. T.rex must have had 6-inch diameter bicep muscles. “Imagine our arm bones worked by muscles the size of our thigh muscles,” says Jack Horner (The Complete T-rex, p. 116). Kenneth Carpenter has called T.rex the “Schwarzenegger of dinosaurs” because it could “hoist 400lbs. toward its body at one time,” (The Complete T-rex, p. 116). T.rex’s lower forearms were much less endowed, meaning that it could not have held much weight out by its claws.
Encourage visitors to touch the replica and ask them what they think it is. Encourage them to make descriptive observations. Because this is a fragile replica (due to articulation) it should be left on the cart and only touched by visitors under supervision. What do you think this is? What do you notice about it?
Encourage visitors to compare the size of T.rex’s arm to their own. How much bigger than you was T.rex? How much bigger were his arms? His legs? What might T.rex have used his arms for? What were their limitations?
This large T.rex tooth comes from the Hell Creek Formation near Fort Peck Reservoir. The tooth is about 65-67 million years old. T.rex teeth were some of the largest of any dinosaur. Only the top 25% of the tooth was visible above the gum line. Serrations along the edge of the tooth for gripping food are visible. T.rex teeth could have penetrated the hide, flesh and bones of another dinosaur in one bite. Each tooth was replaced about every 2-3 years. Tooth replacement continued throughout the animal’s life. This tooth is from G.rex. This tooth is similar in size to those of specimen MOR 008, the world’s largest dinosaur skull. The original G-Rex tooth is on display in the Hall of Horns and Teeth across from the Wankel T.rex skeleton. The tooth shows an example of a large T.rex tooth with the entire tooth and root intact. Also visible on this specimen is the tooth cavity formed from the next incoming tooth. The fact that the entire tooth and root system is intact indicates that the tooth was probably lost after death.
Hand the replica to visitors and ask them what they think it is. Encourage them to make descriptive observations. What do you think this is? What do you notice about it?
Give a visitor the replica and ask them to locate the real one in the exhibit.
Ask visitors which way is up. How much of this replica represents the exposed tooth? How much represents the root?
Have visitors carefully observe the tooth. Whose tooth is this? What kind of food do you think this animal ate?