Utahraptor ("Utah thief") is the largest known genus of the family Dromaeosauridae. Fossil specimens date to the upper Barremian stage of the early Cretaceous period. Utahraptor was one of the most terrifying creatures on planet Earth.
Standing 6 feet (2 meters) tall, a little bit taller than a modern human, measuring 20-23 feet (6-7 meters) long and weighing in at over 1500 pounds, the Utahraptor was the largest known of the Dromeosaurids (popularly known as raptor dinosaurs). Its powerful forelimbs each ended in three curved, blade-like claws, and it walked on two long, sturdy legs with sharp, sickle-like claws ending on its second toes.
Like other dromoaesaurids, Utahraptor may have hunted in packs, which made it an even more fearsome predator. However though often a pack hunter like most of its relatives, Utahraptor fought to bring down its prey with both brains AND brawn, rather than just brains. Fast-moving and agile, with excellent vision, the Utahraptor was nonetheless slower than smaller relatives such as Deinonychus or Velociraptor; it would probably have lain in wait, then pounced on the back of its victim, slashing and tearing apart its flesh with its sharp claws.
Utahraptor's prey possibly included very large herbivorous dinosaurs such as sauropods. When food was scarce, it would even take on the heavily armored ankylosaur Gastonia.
- When it ran, the Utahraptor rotated its middle toe (the one outfitted with its lethal claw) upwards and ran on the other three toes.
- The Utahraptor has only quill knobs on the head and arms although they had feathers all over their bodies excepted their mouth and feet