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Deinonychus Dinosaur Facts for Kids


  • Deinonychus is a genus of carnivorous dromaeosaurid coelurosaurian dinosaurs, with one described species, Deinonychus antirrhopus.
  • This species, which could grow up to 11 ft long, lived during the early Cretaceous Period, about 115–108 million years ago.
  • Fossils have been recovered from the U.S. states of MontanaUtah, Wyoming, and Oklahoma, in rocks of the Cloverly Formation, Cedar Mountain Formation and Antlers Formation, though teeth that may belong to Deinonychus have been found much farther east in Maryland.
  • Paleontologist John Ostrom’s study of Deinonychus in the late 1960s revolutionized the way scientists thought about dinosaurs, leading to the “dinosaur renaissance” and igniting the debate on whether dinosaurs were warm-blooded or cold blooded.
  • Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants.
  • “Terrible claw” refers to the unusually large, sickle-shaped talon on the second toe of each hind foot.
  • Ostrom looked at crocodile and bird claws and reconstructed the claw for YPM 5205 as over 4.7 in long.
  • As in other dromaeosaurids, the tail vertebrae have a series of ossified tendons and super-elongated bone processes.
  • In both the Cloverly and Antlers formations, Deinonychus remains have been found closely associated with those of the ornithopod Tenontosaurus.
  • Teeth discovered associated with Tenontosaurus specimens imply they were hunted, or at least scavenged upon, by Deinonychus.
  • No skin impressions have ever been found in association with fossils of Deinonychus.
  • Deinonychus antirrhopus is one of the best-known dromaeosaurid species, and is a close relative of the smaller Velociraptor, which is found in younger, Late Cretaceous–age rock formations in Central Asia.
  • Fossilized remains of Deinonychus have been recovered from the Cloverly Formation of Montana and Wyoming and in the roughly contemporary Antlers Formation of Oklahoma, in North America.
  • The Cloverly formation has been dated to the late Aptian through early Albian stages of the early Cretaceous, about 115 to 108 Ma. Additionally, teeth found in the Arundel Clay Facies (mid-Aptian), of the Potomac Formation on the Atlantic Coastal Plain of Maryland may be assigned to the genus.
  • Since the association between the various recovered bones was weak, making the exact number of individual animals represented impossible to determine properly, the type specimen (YPM 5205) of Deinonychus was restricted to the complete left foot and partial right foot that definitely belonged to the same individual.
  • A skeleton of Deinonychus, including bones from the original (and most complete) AMNH 3015 specimen, can be seen on display at the American Museum of Natural History, with another specimen (MCZ 4371) on display at the Museum of Comparative Zoology at Harvard University.
  • In a subsequent, more detailed report, on the eggshells, Grellet-Tinner and Makovicky concluded that the egg almost certainly belonged to Deinonychus, representing the first dromaeosaurid egg to be identified.
  • Because of its extremely bird-like anatomy and close relationship to other dromaeosaurids, paleontologists hypothesize that Deinonychus was probably covered in feathers.
  • When conducting studies of such areas as the range of motion in the forelimbs, paleontologists like Phil Senter have taken the likely presence of wing feathers into consideration.
  • A 2010 study by Paul Gignac and colleagues attempted to estimate the bite force based directly on newly discovered Deinonychus tooth puncture marks in the bones of a Tenontosaurus.
  • The type specimen described by Ostrom in 1969 has a strongly curved sickle claw, while a newer specimen described in 1976 had a claw with much weaker curvature, more similar in profile with the ‘normal’ claws on the remaining toes.