Geologic Age: Late Cretaceous, ~65 to 70 million years ago
Rock Units: Lance and Hell Creek Formations
Geographic Range: Western Interior of North America
Adult Length: 15 meters
Adult Height: 6 meters
Adult Weight: 7 tons
Habitat: Lowland floodplains
Tyrannosaurus rex was the largest carnivorous dinosaur. It may have been an active hunter, but it also was a likely scavenger as well. T. rex was one of the last dinosaurs to live in the Mesozoic Era. One of the most popular dinosaurs, T. rex has been the star of movies ranging from "The Lost World" (1925) to "Jurassic Park" (1993). Current research has shown that unlike many of the restorations of this animal in the early part of the 20th century (mostly based on paintings by the famed dinosaur artist Charles R. Knight), T. rex should not be portrayed as a bulky, tail-dragging reptile, but rather as an active, sleek carnivore. It is now believed that its massive tail was held off the ground and used as a counterbalance.