The Dinosaurs and Prehistoric Animals of California

Skull of a saber-tooth tiger

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Although California is best known for its megafauna mammals, such as the Saber-Toothed Tiger and the Dire Wolf as tourist attractions, the state has a deep fossil history stretching all the way back to the Cambrian period. Dinosaurs, unfortunately, are rather lacking. They certainly lived in California, as they did everywhere else in North America during the Mesozoic Era, but thanks to the vagaries of geology, they haven't been preserved well in the fossil record. Here are the most important dinosaurs and prehistoric animals discovered in the Eureka State.

Saber-Tooth Tiger

Saber-toothed tiger fossil
The Saber-Toothed Tiger, a prehistoric animal of California. Wikimedia Commons

The Saber-Tooth Tiger (often referred to by its genus name, Smilodon) is far and away the most famous (and most common) prehistoric mammal of California, thanks to the recovery of literally thousands of complete skeletons from the famous La Brea Tar Pits of downtown Los Angeles. This Pleistocene predator was smart, but clearly not quite smart enough, as entire packs of saber-tooths got trapped in the muck when they attempted to feast on already-mired prey.

Dire Wolf

Skeleton of a dire wolf

Eden, Janine and Jim/Wikimedia Commons/CC BY 2.0

Almost as plentiful in the fossil record as the Saber-Toothed Tiger, the Dire Wolf is a particularly appropriate animal to have lived in California, given its starring role in the HBO series Game of Thrones. As with Smilodon, numerous skeletons of the Dire Wolf (genus and species name Canis dirus) have been dredged out of the La Brea Tar Pits, demonstrating that these two muscular, roughly equally sized megafauna mammals competed for the same prey.



Karkemish/Wikimedia Commons/CC BY 3.0

The only dinosaur ever to be discovered in southern California, and of the few dinosaurs to be discovered in the entire state, Aletopelta was a 20-foot-long, two-ton ankylosaur, and thus a close relative of the much later and better-known Ankylosaurus. Like many prehistoric animals, Aletopelta was discovered completely by accident; a road crew was doing construction work near Carlsbad, and the fossil of Aletopelta was recovered from a ditch that had been excavated for a sewer pipe.


The Ichthyosaur species

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Californosaurus is one of the most primitive ichthyosaurs ("fish lizards") yet identified in the fossil record, as betrayed by this marine reptile's relatively un-hydrodynamic shape (a short head perched on a bulbous body) and comparably short flippers. Confusingly, this late Triassic fish-eater is often referred to as Shastasaurus or Delphinosaurus, but paleontologists prefer Californosaurus, probably because it's more fun.


Illustration of a Plotosaurus

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One of the few prehistoric animals ever to be discovered near Fresno, Plotosaurus was a 40-foot-long, five-ton mosasaur, the family of marine reptiles that dominated the world's oceans toward the end of the Cretaceous period. The unusually large eyes of Plotosaurus point to it being an especially effective predator of other marine reptiles, but not, unfortunately, effective enough not to be rendered extinct, along with all of its mosasaur relatives, by the K/T Meteor Impact.


The Cetotherium species

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The prehistoric whale Cetotherium, one species of which prowled the shores of California millions of years ago, can be considered a smaller, sleeker version of the modern gray whale. Like its modern descendant, Cetotherium filtered plankton from seawater with the aid of baleen plates. It was probably preyed upon by the giant prehistoric sharks of the Miocene epoch, a roster that includes the 50-foot-long, 50-ton Megalodon, the largest prehistoric shark that ever lived.

Various Megafauna Mammals

The Megafauna species

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Although the Saber-Toothed Tiger and the Dire Wolf are the most famous megafauna mammals to be recovered from the La Brea Tar Pits, they were far from the only comically gigantic furry beasts of Pleistocene California. Also prowling this state were the American Mastodon, the Giant Ground Sloth, and the Giant Short-Faced Bear, all of which went extinct shortly after the last Ice Age, victims of climate change as well as hunting by Native American tribes.

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Strauss, Bob. "The Dinosaurs and Prehistoric Animals of California." ThoughtCo, Sep. 8, 2021, Strauss, Bob. (2021, September 8). The Dinosaurs and Prehistoric Animals of California. Retrieved from Strauss, Bob. "The Dinosaurs and Prehistoric Animals of California." ThoughtCo. (accessed June 2, 2023).