Rarely has a single movie so permanently twisted peoples' views of an entire family of dinosaurs. In Steven Spielberg's Jurassic Park, Velociraptor is presented as a man-sized, scaly-skinned predator smart enough to turn doorknobs. In real life, though, this dinosaur was only the size of a small toddler, probably covered in feathers, and not quite as intelligent as the average hummingbird. (For the record, what are called Velociraptors in Jurassic Park were really much bigger Deinonychuses, but let's not quibble.) See a gallery of raptor pictures
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The time has clearly come to set the record on raptors straight. For one thing, you might be surprised to learn that "raptor" itself is a mass-market, Hollywood-type name: paleontologists prefer to speak of "dromaeosaurs" (Greek for "running lizards"), which isn't quite as catchy. And for another, the raptor roster extends far beyond the popular Velociraptor and Deinonychus, as explained below. (By the way, not all dinosaurs with "raptor" in their names are true dromaeosaurs; examples are Oviraptor and Eoraptor.)
What Is a Raptor?
Technically, paleontologists define dromaeosaurs as dinosaurs that share certain obscure anatomical features. Broadly speaking, though, raptors can be classified as small- to medium-sized, bipedal carnivores equipped with grasping, three-fingered hands and relatively big brains. Most distinctively, raptors had huge, solitary claws on each of their hind feet, which they probably used to slash (and sometimes disembowel) prey.
Then there's the issue of feathers. While it can't be flatly stated that all dromaeosaurs had feathers, enough fossils have been found bearing evidence of this unmistakeably bird-like trait to lead paleontologists to conclude that feathered raptors were the norm, rather than the exception. Some genuses (such as Microraptor) were capable of gliding, and some experts even speculate that raptors descended from flying (non-bird) ancestors. In any case, dromaeosaurs are closely related to modern birds; the name "raptor" also embraces modern eagles and falcons.
The Rise of the Raptors
Raptors came into their own during the late Cretaceous period (about 90 to 65 million years ago), but they may have roamed the earth a hundred million years before (paleontologists have yet to dig up any fossils, but they have found distinctly dromaeosaur-like teeth dating from this time). It's likely that these early raptors were relatively tiny, scurrying under the feet of the larger sauropods of the middle to late Jurassic.
In the Cretaceous, raptors could be found all over the planet, with the exception of modern-day Australia and southern Africa. These creatures varied enormously in size and sometimes in anatomical features: Microraptor weighed only a few pounds and had four feathered proto-wings, while the fierce, two-ton Utahraptor could have whomped a Deinonychus with one claw tied behind its back. In between were standard-issue raptors like Dromaeosaurus and Saurornitholestes, swift, fierce predators that made quick meals out of lizards, bugs, and smaller dinosaurs.
Raptor Behavior
While even the brainiest raptor couldn't outwit a siamese cat, much less a human being, it's clear that dromaeosaurs were slightly smarter than their fellow dinosaurs (this increase in brain size can be directly linked to the eye-hand coordination required for active predation, since swifter reflexes translate into more frequent meals).
As to whether or not raptors hunted in packs, that debate has yet to be settled conclusively one way or the other. The fact is, very few modern birds engage in cooperative hunting; since birds are tens of millions of years farther down the evolutionary line, that can be taken as evidence that raptor packs are a figment of a Hollywood producer's imagination. Still, the recent discovery of multiple dromaeosaur tracks shows that at least some of these dinosaurs lived in small herds, so pack hunting is certainly within the realm of possibility.
Here's a list of the most notable raptors; just click on the links for more information.
Achillobator This fierce raptor was discovered in modern-day Mongolia.
Bambiraptor Yes, this tiny raptor was named after you-know-who.
Buitreraptor The oldest raptor ever discovered in South America.
Deinonychus One of the most fearsome predators of the Cretaceous era.
Dromaeosaurus This "running lizard" was probably covered with feathers.
Microraptor This tiny proto-bird had four wings rather than two.
Pyroraptor This "fire thief" prowled the plains of prehistoric France.
Rahonavis Was it a raptor-like bird, or a bird-like raptor?
Saurornitholestes A close cousin of Velociraptor.
Unenlagia This bird-like raptor was native to South America.
Utahraptor Probably the biggest raptor that ever lived.
Velociraptor This dino was vicious--but a lot smaller than you thought.