Deinonychus

(die-NON-ick-us)

Name means: Terrible Claw

 

Species: antirrhopus

Range: Early Cretaceous (Albian, 112-109 MYA) from Montana, Utah, Wyoming, Oklahoma

Size estimate: 10-11 ft length, 160-220 lbs

Discovery: John Ostrom, 1969

Classification: dinosauria, saurischia, therapoda, maniraptora, dromeosauridae

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After Jurassic Park catapulted Velociraptor into pop stardom, many among the general public tend to conflate all small meat-eating dinosaurs with the raptor group (technically they’re known as the maniraptors, which means “grabby hands”). However, raptors show a bunch of features that set them apart from other small carnivorous dinosaurs like Coelophysis or Ornitholestes. To get a better “grip” on Deinonychus itself, check out these cool tidbits:

 

• What’s the real difference between maniraptors and other small theropods? The main difference lies in the crescent moon-shaped bone of the wrist that gives maniraptors more flexibility with their hands. Dromaeosaurs—the raptor group that includes Deinonychus—also had the distinctive toe claws and bony rods in their tails that give this animal its name, which means “counterbalanced terror claw.” True raptors also lived during the late Jurassic through the Cretaceous (Deinonychus itself lived in the early Cretaceous along with Acrocanthosaurus and Tenontosaurus; Coelophysis and Ornitholestes both lived much earlier).

• Up until the discovery of Utahraptor in 1993, Deinonychus weighed in as the real bruiser of the raptor clan at up to 11 feet and a whopping 150-225 pounds. Since the discoveries of giant raptors like Utahraptor, Dakotaraptor, Austroraptor, and Achillobator, it fits into the mid-sized range.

• Scientists currently lack direct evidence for this animal’s skin covering, but enough of its close relatives show evidence of feathers that we can be reasonably certain it had them too. Its size means it didn’t use them for flight, but they were anchored into the bones like modern flying birds, so they served a function that subjected them to physical stress. One current hypothesis posits they may have stabilized the animal while it used its famous killing claw for a death grip attack on its prey.

  —Jeff Bond

   

  Temporary Reference

  Since the sign for the Deinonychus duo across the river has not yet been posted, please refer instead to the following information:
  
  During the early 1970’s scientists’ views on dinosaurs began to change. For a hundred years most people thought of dinosaurs as sluggish, giant lizards. The discovery of Deinonychus helped change that point of view. Its bones share far more features with birds than with lizards. Though it belonged to the lizard-hipped saurischian group of dinosaurs, its hips looked more like birds’ than lizards’. Its hollow bones, counterbalancing tail, and legs built for speed implied a high-energy lifestyle. Its agile arms and large brain suggest complex behavior. Dinosaurs like Deinonychus led scientists to question long-standing beliefs like cold-blooded metabolism or simplistic behavior. This led to a new era in the history of paleontology some call “The Dinosaur Renaissance.”

   

  Our ideas about Deinonychus have changed drastically during the last 45 years. These sculptures represent the animal from the old point of view. Compare them with the Deinonychus on the other side of the river, which follow the Dinosaur Renaissance point of view. The statues here have agile arms like they should, but the wrists bend the wrong way for this group of animals. Theropods could not bend the palms of their hands toward the ground without moving their whole arms. Though we don’t have direct evidence for Deinonychus skin, enough other raptor-type dinosaurs show evidence of bird-like feathers that it likely had them too. More importantly, raptor feathers anchored to the bone like on some birds’ wings, which means they may have used them for balance while killing prey. On the other hand, these statues have more true-to-life heads than the ones across the river. Deinonychus skull bones don’t preserve well, but the first skeleton found had some of them. When John Ostrom reconstructed them, he used Allosaurus as a model. These sculptures use that model, while the other statues use Velociraptor heads. A recent find showed that Deinonychus’ skull more closely resembled Ostrom’s version.

 

During the early 1970’s scientists’ views on dinosaurs began to change. For a hundred years most people thought of dinosaurs as sluggish, giant lizards. The discovery of Deinonychus helped change that point of view. Its bones share far more features with birds than with lizards. Though it belonged to the lizard-hipped saurischian group of dinosaurs, its hips looked more like birds’ than lizards’. Its hollow bones, counterbalancing tail, and legs built for speed implied a high-energy lifestyle. Its agile arms and large brain suggest complex behavior. Dinosaurs like Deinonychus led scientists to question long-standing beliefs like cold-blooded metabolism or simplistic behavior. This led to a new era in the history of paleontology some call “The Dinosaur Renaissance.”

Our ideas about Deinonychus have changed drastically during the last 45 years. These sculptures represent the animal from the old point of view. Compare them with the Deinonychus on the other side of the river, which follow the Dinosaur Renaissance point of view. The statues here have agile arms like they should, but the wrists bend the wrong way for this group of animals. Theropods could not bend the palms of their hands toward the ground without moving their whole arms. Though we don’t have direct evidence for Deinonychus skin, enough other raptor-type dinosaurs show evidence of bird-like feathers that it likely had them too. More importantly, raptor feathers anchored to the bone like on some birds’ wings, which means they may have used them for balance while killing prey. On the other hand, these statues have more true-to-life heads than the ones across the river. Deinonychus skull bones don’t preserve well, but the first skeleton found had some of them. When John Ostrom reconstructed them, he used Allosaurus as a model. These sculptures use that model, while the other statues use Velociraptor heads. A recent find showed that Deinonychus’ skull more closely resembled Ostrom’s version.

Refer to the Deinonychus sign across the river for more information on this animal.