Velociraptor is a genus of dromaeosaurid theropod dinosaur that lived approximately 75 to 71 million years ago during the latter part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils of this species have been discovered in Mongolia. A second species, V. osmolskae, was named in 2008 for skull material from Inner Mongolia, China.
Smaller than other dromaeosaurids like Deinonychus and Achillobator, Velociraptor nevertheless shared many of the same anatomical features. It was a bipedal, feathered carnivore with a long tail and an enlarged sickle-shaped claw on each hindfoot, which is thought to have been used to tackle and disembowel prey. Velociraptor can be distinguished from other dromaeosaurids by its long and low skull, with an upturned snout.
Velociraptor (commonly shortened to “raptor”) is one of the dinosaur genera most familiar to the general public due to its prominent role in the Jurassic Park motion picture series. In real life, however, Velociraptor was roughly the size of a turkey, considerably smaller than the approximately 2 m (7 ft) tall and 80 kg (180 lb) reptiles seen in the films (which were based on members of the related genus Deinonychus). Today, Velociraptor is well known to paleontologists, with over a dozen described fossil skeletons, the most of any dromaeosaurid. One particularly famous specimen preserves a Velociraptor locked in combat with a Protoceratops.
Velociraptor was a mid-sized dromaeosaurid, with adults measuring up to 2.07 m (6.8 ft) long, 0.5 m (1.6 ft) high at the hip, and weighing up to 15 kg (33 lb), though there is a higher estimate of 19.7 kg (43 lb). The skull, which grew up to 25 cm (9.8 in) long, was uniquely up-curved, concave on the upper surface and convex on the lower. The jaws were lined with 26–28 widely spaced teeth on each side, each more strongly serrated on the back edge than the front.
Velociraptor, like other dromaeosaurids, had a large manus (‘hand’) with three strongly curved claws, which were similar in construction and flexibility to the wing bones of modern birds. The second digit was the longest of the three digits present, while the first was shortest. The structure of the carpal (wrist) bones prevented pronation of the wrist and forced the ‘hands’ to be held with the palmar surface facing inwards (medially), not downwards. The first digit of the foot, as in other theropods, was a small dewclaw. However, whereas most theropods had feet with three digits contacting the ground, dromaeosaurids like Velociraptor walked on only their third and fourth digits. The second digit, for which Velociraptor is most famous, was highly modified and held retracted off the ground. It bore a relatively large, sickle-shaped claw, typical of dromaeosaurid and troodontid dinosaurs. This enlarged claw, which could grow to over 6.5 cm (2.6 in) long around its outer edge, was most likely a predatory device used to tear into or restrain struggling prey.