10 Facts About Deinonychus, the Terrible Claw

Deinonychus in the act of eating
Deinonychus in the act of eating.

 Emily Willoughby/Stocktrek Images / Getty Images

It's not nearly as well-known as its Asian cousin, Velociraptor, which it played in Jurassic Park and Jurassic World, but Deinonychus is far more influential among paleontologists--and its numerous fossils have shed valuable light on the appearance and behavior of raptor dinosaurs. Below, you'll discover 10 fascinating Deinonychus facts.

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Deinonychus is Greek for "Terrible Claw"

deinonychus skeleton
deinonychus skeleton.

 Wikimedia Commons

The name Deinonychus (pronounced die-NON-ih-kuss) references the single, large, curving claws on each of this dinosaur's hind feet, a diagnostic trait that it shared with its fellow raptors of the middle to late Cretaceous period. (The "deino" in Deinonychus, by the way, is the same Greek root as the "dino" in dinosaur, and is also shared by such prehistoric reptiles as Deinosuchus and Deinocheirus.) 

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Deinonychus Inspired the Theory that Birds Descended from Dinosaurs

Deinonychus with fethers

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In the late 1960's and early 1970's, the American paleontologist John H. Ostrom remarked on the similarity of Deinonychus to modern birds--and he was the first paleontologist to broach the idea that birds evolved from dinosaurs. What seemed like a wacky theory a few decades ago is today accepted as fact by most of the scientific community, and has been heavily promoted over the last few decades by (among others) Ostrom's disciple, Robert Bakker.

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Deinonychus Was (Almost Certainly) Covered with Feathers


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Today, paleontologists believe that most theropod dinosaurs (including raptors and tyrannosaurs) sported feathers at some stage in their life cycles. To date, no direct evidence has been adduced for Deinonychus having feathers, but the proven existence of other feathered raptors (such as Velociraptor) implies that this larger North American raptor must have looked at least a little bit like Big Bird--if not when it was fully grown, then at least when it was a juvenile.

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The First Fossils Were Discovered in 1931

Deinonychus skeleton

 Wikimedia Commons

Ironically, the famous American fossil hunter Barnum Brown discovered the type specimen of Deinonychus while he was on the prowl in Montana for an entirely different dinosaur, the hadrosaur, or duck-billed dinosaur, Tenontosaurus (about which more in slide #8). Brown didn't seem all that interested in the smaller, less headline-worthy raptor he had serendipitously excavated, and provisionally named it "Daptosaurus" before forgetting about it entirely. 

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Deinonychus Used its Hind Claws to Disembowel Prey

deinonychus hind claws

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Paleontologists are still trying to figure out exactly how raptors wielded their hind claws, but it's a sure bet that these razor-sharp implements had some kind of offensive function (in addition to, conceivably, helping their owners climb trees when they were being pursued by larger theropods, or impressing the opposite sex during mating season). Deinonychus probably used its claws to inflict deep stab wounds on its prey, perhaps withdrawing to a safe distance afterward and waiting for its dinner to bleed to death.

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Deinonychus Was the Model for Jurassic Park's Velociraptors


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Remember those scary, man-sized, pack-hunting Velociraptors from the first Jurassic Park movie, and their beefed-up military counterparts in Jurassic World? Well, those dinosaurs were really modeled on Deinonychus, a name that these films' producers presumably considered too hard for audiences to pronounce. (By the way, there's no chance that Deinonychus, or any other dinosaur, was smart enough to turn doorknobs, and it almost certainly didn't possess green, scaly skin, either.)

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Deinonychus May Have Preyed on Tenontosaurus

Tenontosaurus warding off a pack of Deinonychus.

 Alain Beneteau / Getty Images

The fossils of Deinonychus are "associated" with those of the duck-billed dinosaur Tenontosaurus, which means that these two dinosaurs shared the same North American territory during the middle Cretaceous period and lived and died in close proximity to each other. It's tempting to draw the conclusion that Deinonychus preyed on Tenontosaurus, but the problem is that full-grown Tenontosaurus adults weighed about two tons--meaning that Deinonychus would have had to hunt in cooperative packs!

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The Jaws of Deinonychus Were Surprisingly Weak

deinonychus skull

 Wikimedia Commons

Detailed studies have shown that Deinonychus had a fairly wimpy bite compared to other, larger theropod dinosaurs of the Cretaceous period, such as the orders-of-magnitude bigger Tyrannosaurus Rex and Spinosaurus--only about as powerful, in fact, as the bite of a modern alligator. This makes sense, given that this slender raptor's primary weapons were its curved hind claws and long, grasping hands, rendering extra-strong jaws superfluous from an evolutionary standpoint.

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Deinonychus Wasn't the Fastest Dinosaur on the Block


 Emily Willoughby / Getty Images

One more detail that Jurassic Park and Jurassic World got wrong about Deinonychus (aka Velociraptor) was this raptor's pulse-pounding speed and agility. It turns out that Deinonychus wasn't nearly as agile as other theropod dinosaurs, such as the fleet-footed ornithomimids, or "bird mimics," though one recent analysis shows that it may have been capable of trotting at a brisk clip of six miles per hour when pursuing prey (and if that sounds slow, try doing it yourself).

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The First Deinonychus Egg Wasn't Discovered Until 2000

A Deinonychus brooding.

 Steve O'Connell / Getty Images

Although we have ample fossil evidence for the eggs of other North American theropods--most notably Troodon--Deinonychus eggs have been comparatively thin on the ground. The only likely candidate (which still hasn't been conclusively identified) was discovered in 2000, and subsequent analysis hints that Deinonychus gestated its young much like the similarly sized feathered dinosaur Citipati (which wasn't technically a raptor, but a kind of theropod known as an oviraptor).