The Dinosaurs and Prehistoric Animals of South Dakota

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Which Dinosaurs and Prehistoric Animals Lived in South Dakota?

tyrannosaurus rex
Tyrannosaurus Rex, a dinosaur of South Dakota. Karen Carr

South Dakota may not be able to boast quite as many dinosaur discoveries as its close neighbors Wyoming and Montana, but this state was home to an unusually wide range of wildlife during the Mesozoic and Cenozic eras, including not only raptors and tyrannosaurs, but prehistoric turtles and megafauna mammals as well. On the following slides, you'll discover the dinosaurs and prehistoric animals for which South Dakota is famous, ranging from the recently discovered Dakotaraptor to the long-since-named Tyrannosaurus Rex. (See a list of dinosaurs and prehistoric animals discovered in each U.S. state.)

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Dakotaraptor, a dinosaur of South Dakota. Emily Willoughby

Recently discovered in South Dakota's portion of the Hell Creek formation, Dakotaraptor was a 15-foot-long, half-ton raptor that lived at the very end of the Cretaceous period, right before the dinosaurs were rendered extinct by the K/T meteor impact. As huge as it was, though, the feathered Dakotaraptor was still outclassed by Utahraptor, a 1,500-pound dinosaur that preceded it by about 30 million years (and was named, you guessed it, after the state of Utah).

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Tyrannosaurus Rex

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Tyrannosaurus Rex, a dinosaur of South Dakota. Wikimedia Commons

Late Cretaceous South Dakota was home to one of the most famous Tyrannosaurus Rex specimens of all time: Tyrannosaurus Sue, which was discovered by amateur fossil hunter Sue Hendrickson in 1990. After protracted disputes about Sue's provenance--the owner of the property on which she was excavated claimed legal custody--the reconstructed skeleton wound up being auctioned off to the Field Museum of Natural History (in far-off Chicago) for eight million dollars.

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Triceratops, a dinosaur of South Dakota. National Museum of Natural History

The second-most-famous dinosaur of all time--after Tyrannosaurus Rex (see previous slide)--numerous specimens of Triceratops have been discovered in South Dakota, as well as surrounding states. This ceratopsian, or horned, frilled dinosaur, possessed one of the largest, most ornate heads of any creature in the history of life on earth; even today, fossilized Triceratops skulls, with their horns intact, command big bucks at natural-history auctions.

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Barosaurus, a dinosaur of South Dakota. Wikimedia Commons

Since South Dakota was submerged underwater for much of the Jurassic period, it hasn't yielded many fossils of famous sauropods like Diplodocus or Brachiosaurus. The best the Mount Rushmore State can offer is Barosaurus, the "heavy lizard," a comparably sized cousin of Diplodocus blessed with an even longer neck. (A famous Barosaurus skeleton at the American Museum of Natural History shows this sauropod rearing up on its hind legs, a problematic pose given its likely cold-blooded metabolism.)

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Various Herbivorous Dinosaurs

Dracorex hogwartsia, a dinosaur of South Dakota. Children's Museum of Indianapolis

One of the first ornithopod dinosaurs to be discovered in the United States, Camptosaurus has a complicated taxonomic history. The type specimen was unearthed in Wyoming, in 1879, and a separate species a few decades later in South Dakota, later renamed Osmakasaurus. South Dakota has also yielded scattered remains of the armored dinosaur Edmontonia, the duck-billed dinosaur Edmontosaurus, and the head-butting Pachycephalosaurus (which may or may not be the same animal as another famous South Dakota resident, Dracorex hogwartsia, named after the Harry Potter books).

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Archelon, a prehistoric turtle of South Dakota. Wikimedia Commons

The largest prehistoric turtle that ever lived, the "type fossil" of Archelon was discovered in South Dakota in 1895 (an even bigger individual, measuring over a dozen feet long and weighing over two tons, was unearthed in the 1970's; just to put things in perspective, the largest testudine alive today, the Galapagos Tortoise, only weighs about 500 pounds). The closest living relative of Archelon alive today is the soft-shelled sea turtle known as the Leatherback.

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Brontotherium, a prehistoric mammal of South Dakota. Wikimedia Commons

Dinosaurs weren't the only giant animals to live in South Dakota. Tens of millions of years after the dinosaurs went extinct, megafauna mammals like Brontotherium roamed the western plains of North America in large, lumbering herds. This "thunder beast" did have one trait in common with its reptilian predecessors, though: its unusually small brain, which may help to explain why it vanished off the face of the earth by the start of the Oligocene epoch, 30 million years ago.

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Hyaenodon, a prehistoric mammal of South Dakota. Wikimedia Commons

One of the longest-lasting predatory mammals in the fossil record, various species of Hyaenodon persisted in North America for a whopping 20 million years, from forty million to twenty million years ago. Numerous specimens of this wolf-like carnivore (which, however, was only remotely ancestral to modern canines) have been unearthed in South Dakota, where Hyaenodon preyed on plant-eating megafauna mammals, possibly including the juveniles of Brontotherium (see previous slide).

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Poebrotherium, a prehistoric mammal of South Dakota. Wikimedia Commons

A contemporary of Brontotherium and Hyaenodon, described in the previous slides, Poebrotherium ("grass-eating beast") is the best-known prehistoric camel of South Dakota. If you find this surprising, you may be intrigued to learn that camels originally evolved in North America, but went extinct on the cusp of the modern era, by which time they had already spread into Eurasia. (Poebrotherium didn't look much like a camel, by the way, since it was only three feet tall at the shoulder and weighed 100 pounds!)

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Your Citation
Strauss, Bob. "The Dinosaurs and Prehistoric Animals of South Dakota." ThoughtCo, Feb. 16, 2021, Strauss, Bob. (2021, February 16). The Dinosaurs and Prehistoric Animals of South Dakota. Retrieved from Strauss, Bob. "The Dinosaurs and Prehistoric Animals of South Dakota." ThoughtCo. (accessed June 7, 2023).