Replica of a skull with lower jaws featuring sharp, serrated teeth. This life-sized cast is from an Allosaurus skeleton excavated at the Dinosaur National Monument in Utah and Colorado.

This carnivorous dinosaur, measuring over 8.5 meters in length, was a true killing machine. Nearly complete skeletons of this dinosaur species have been unearthed in North America, and the species is also known from Portugal in Europe. Young Allosauruses may have had feathers, but it is known that adult individuals had scales.

This Allosaurus lived at the end of the Jurassic period, between 155 million and 150 million years ago. The genus name Allosaurus means “different lizard,” and the species name fragilis refers to the lightly built, very fragile vertebrae.