Fragmentary Utahraptor fossils were first discovered in what is today eastern Utah in 1991. Now a high plateau, during the early Cretaceous Period about 125 million years ago this was a mostly arid savannah dotted with ponds that attracted a variety of creatures.


Much bigger than dromaeosaurids, or raptors, of later eras, including the Deinonychus and Velociraptor, fossils indicate the Utahraptor could be up to 20 feet long and weigh about a ton. It had a large jaw with short, sharp teeth and large bladelike claws on its forefeet and other such slashing weapons on its toes. The creature stood on its two back legs, standing about 7 feet tall. With its muscular arms and legs, the Utahraptor is believed to have been a particularly dangerous and efficient killer.


A meat-eating predator and scavenger, the Utahraptor could probably outrun its live prey, which apparently included plant-eating ankylosaurs and larger sauropods. It may have stalked in packs or on its own.


"Raptor" dinosaurs get their name from a Latin word for "thief" or "robber." The term is also used for modern birds that hunt their prey, such as eagles and hawks. Utahraptor can be translated as "Utah thief" or, more mildly, "Utah hunter." "In its day," says Dr. Jim Kirkland of Dinamation International Society, who first identified Utahraptor with scientists from the College of Eastern Utah, "it was probably the nastiest animal around."

Sources: Utah Museum of Natural History; College of Eastern Utah Prehistoric Museum