Velociraptor

***Velociraptor*** (meaning "swift seizer") 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 tear into 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 (6+1⁄2 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*.

## Description

*Velociraptor* was a mid-sized dromaeosaurid, with adults measuring up to 2.07 m (6 ft 9+1⁄2 in) long, 0.5 m (1 ft 7+1⁄2 in) high at the hip, and weighing up to 15 kg (33 lb), though there is a higher estimate of 19.7 kg (43+1⁄2 lb). The skull, which grew up to 25 cm (10 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 inward (medially), not downward. 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+1⁄2 in) long around its outer edge, was most likely a predatory device used to tear into or restrain struggling prey.

As in other dromaeosaurs, *Velociraptor* tails had long bony projections (prezygapophyses) on the upper surfaces of the vertebrae, as well as ossified tendons underneath. The prezygapophyses began on the tenth tail (caudal) vertebra and extended forward to brace four to ten additional vertebrae, depending on position in the tail. These were once thought to fully stiffen the tail, forcing the entire tail to act as a single rod-like unit. However, at least one specimen has preserved a series of intact tail vertebrae curved sideways into an *S*-shape, suggesting that there was considerably more horizontal flexibility than once thought.

### Feathers

Fossils of dromaeosaurids more primitive than *Velociraptor* are known to have had feathers covering their bodies and fully developed feathered wings. The fact that the ancestors of *Velociraptor* were feathered and possibly capable of flight had long suggested to paleontologists that *Velociraptor* bore feathers as well, since even flightless birds today retain most of their feathers. In September 2007, researchers found quill knobs on the forearm of a *Velociraptor* found in Mongolia. These bumps on bird wing bones show where feathers anchor, and their presence on *Velociraptor* indicate it too had feathers.

According to Turner and co-authors Norell and Peter Makovicky, quill knobs are not found in all prehistoric birds, and their absence does not mean that an animal was not feathered, flamingos, for example, have no quill knobs. However, their presence confirms that *Velociraptor* bore modern-style wing feathers, with a rachis and vane formed by barbs. The forearm specimen on which the quill knobs were found (specimen number IGM 100/981) represents an animal 1.5 meters (4 feet 11 inches) in length and 15 kilograms (33 pounds) in weight. Based on the spacing of the six preserved knobs in this specimen, the authors suggested that *Velociraptor* bore 14 secondaries (wing feathers stemming from the forearm), compared with 12 or more in *Archaeopteryx*, 18 in *Microraptor*, and 10 in *Rahonavis*. This type of variation in the number of wing feathers between closely related species, the authors asserted, is to be expected, given similar variation among modern birds.

Turner and colleagues interpreted the presence of feathers on *Velociraptor* as evidence against the idea that the larger, flightless maniraptorans lost their feathers secondarily due to larger body size. Furthermore, they noted that quill knobs are almost never found in flightless bird species today, and that their presence in *Velociraptor* (presumed to have been flightless due to its relatively large size and short forelimbs) is evidence that the ancestors of dromaeosaurids could fly, making *Velociraptor* and other large members of this family secondarily flightless, though it is possible the large wing feathers inferred in the ancestors of *Velociraptor* had a purpose other than flight. The feathers of the flightless *Velociraptor* may have been used for display, for covering their nests while brooding, or for added speed and thrust when running up inclined slopes.

## *Velociraptor* in The Amazing Dinosaur Adventure

A duo of *Velociraptor* from the opening narration to *The Time of the Great Giving*