Tyrannosaurus Rex

Name:
Tyrannosaurus Rex (Greek for "tyrant lizard king"); pronounced tih-RAN-oh-SORE-us REX
Habitat:
Forests and swamps of North America
Historical Period:
Late Cretaceous (70-65 million years ago)
Size and Weight:
About 40 feet long and 7 tons
Diet:
Other dinosaurs
Distinguishing Characteristics:
Large head with numerous teeth; stubby, almost vestigial arms
About Tyrannosaurus Rex:

Tyrannosaurus Rex is by far the most popular of all dinosaurs, spawning a huge number of books, movies, TV shows and video games. What's truly amazing, though, is how much about this carnivore that was once assumed as fact has lately been called into question. (See more facts, figures and news about Tyrannosaurus Rex, as well as a gallery of Tyrannosaurus Rex pictures and 10 Facts About T. Rex.)

For example, one controversy that's currently making the rounds among paleontologists is whether T. Rex was a hunter or scavenger. Some experts think T. Rex feasted on already dead prey, on the premise that it couldn't have been fast enough or smart enough to hunt down other dinosaurs--but it was equipped with features (such as a superior sense of smell) that are found in modern scavengers, like vultures. In another development, it's now believed that T. Rex individuals may have succumbed to trichomonosis, a parasitic disease that affects modern birds, and it's entirely possible that T. Rex juveniles were covered in downy coats of feathers, at least to judge by another genus of tyrannosaur, the Asian Dilong.

Despite how it's depicted in action movies, we don't know for sure how speedy Tyrannosaurus Rex was. Unlike the juggernaut of the Jurassic Park movies, it's possible that this dinosaur lumbered along at a poky 10 miles per hour, max--meaning a hungry female would have found it hard to outrun a kid on a bicycle! (For the record, other theropods of the late Cretaceous period, notably the ornithomimids, were capable of sprinting at a zippy 50 miles per hour or so.)