The Dinosaurs and Prehistoric Animals of California

Fossil skeleton of a sabre-toothed tiger.
Print Collector/Getty Images / Getty Images

Although California is best known for its megafauna mammals--you can't beat the Saber-Toothed Tiger and the Dire Wolf as tourist attractions--this 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. On the following slides, you'll discover the most important dinosaurs and prehistoric animals discovered in the Eureka State.

Saber-Tooth Tiger

saber-toothed tiger
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

dire wolf
The Dire Wolf, a prehistoric animal of California. Daniel Auger

Almost as plentiful in the fossil record as the Saber-Toothed Tiger (see previous slide), 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!


Aletopelta, a dinosaur of California. Eduardo Camarga

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!


Californosaurus, a marine reptile of California. Nobu Tamura

Californosaurus is one of the most primitive ichthyosaurs ("fish lizards") yet identified in the fossil record, as betrayed by this marine reptile's relatively unhydrodynamic 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.


Plotosaurus, a marine reptile of California. Flickr

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.


Cetotherium, a prehistoric whale of California. Wikimedia Commons

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, and it was probably preyed on 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

Megatherium, a prehistoric animal of California. Sameer Prehistorica

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 (to name just a few) 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.