Jose Mier is no paleontologist, but he’s taking on the responsibility of searching for dinosaurs (if any exist) in Sun Valley, CA. One can visit the Simi Valley Tar Pits which is only a few minutes drive (and hike) from Sun Valley and there’s always the Cabazon Dinosaurs, just outside of Palm Springs, that, while not real, are a lot of fun.
Southern California is not usually the first place people think of when discussing dinosaurs, but the region has a fascinating prehistoric history that stretches back hundreds of millions of years. Long before modern cities like Los Angeles, Simi Valley, or Sun Valley existed, the landscape of Southern California was dramatically different. Over immense spans of geologic time, the region shifted from shallow seas to coastal plains, forests, and inland basins. These changing environments supported a wide variety of ancient life, including marine reptiles, early mammals, and in some areas, dinosaurs whose fossils occasionally appear in the region’s rock formations.
The story of dinosaurs in Southern California begins during the Mesozoic Era, which lasted from about 252 to 66 million years ago. This era is divided into three major periods: the Triassic, Jurassic, and Cretaceous. Dinosaurs first appeared during the Triassic period and eventually became the dominant land animals across much of the world. However, the geology of what is now Southern California during much of this time was quite different from that of the interior of North America. Large portions of the region were submerged beneath ancient seas, meaning that marine sediments rather than terrestrial deposits were forming. As a result, fossils from this area more commonly include marine organisms such as ammonites, mollusks, and marine reptiles rather than large numbers of land-dwelling dinosaurs.
Despite these challenges, paleontologists have discovered evidence that dinosaurs did indeed inhabit parts of Southern California, especially during the late Cretaceous period roughly 100 to 66 million years ago. At that time, the western edge of North America was a dynamic environment shaped by tectonic activity along the continental margin. River systems, coastal plains, and wetlands existed in areas that are now part of Southern California, providing suitable habitats for dinosaurs and other terrestrial animals.
Some dinosaur fossils discovered in Southern California have been fragmentary—isolated bones, teeth, or trackways rather than complete skeletons. These fragments nonetheless offer valuable clues about the types of dinosaurs that once lived in the region. For example, paleontologists have found evidence suggesting the presence of hadrosaurs, often called “duck-billed dinosaurs.” These herbivorous dinosaurs were among the most common plant-eating species during the late Cretaceous and likely roamed coastal plains feeding on vegetation. Their fossils have been discovered in various parts of California, including areas farther south near the coast.
In addition to hadrosaurs, there is also evidence that armored dinosaurs such as ankylosaurs may have lived in the region. These dinosaurs were heavily protected by bony plates and sometimes tail clubs, making them well defended against predators. Carnivorous dinosaurs also existed in western North America during the Cretaceous, including relatives of tyrannosaurs and smaller predatory theropods, though fossil evidence of them in Southern California is relatively scarce compared to inland areas.
One of the reasons dinosaur fossils are less common in Southern California than in other parts of the United States is the region’s complex geologic history. The area sits near the boundary of several tectonic plates, and the landscape has been heavily reshaped by earthquakes, mountain building, and erosion over millions of years. These forces can destroy or distort fossil-bearing layers, making it more difficult for paleontologists to find intact specimens. In addition, many rock formations that would contain dinosaur fossils are now buried beneath modern urban development.
While dinosaur fossils are relatively rare in the immediate Los Angeles region, Southern California is still famous for its remarkable fossil deposits from more recent prehistoric periods. One well-known example is the La Brea Tar Pits, which have preserved thousands of fossils from the Ice Age. Although these tar pits primarily contain mammals such as saber-toothed cats, dire wolves, and mammoths rather than dinosaurs, they demonstrate how natural asphalt deposits can preserve ancient life in extraordinary detail.
A lesser-known but interesting geological feature in the region is the Simi Valley Tar Pits. Located in the hills of Simi Valley, these natural asphalt seeps occur where petroleum rises through cracks in underground rock layers and the lighter components evaporate, leaving thick asphalt behind. Like the La Brea deposits, these tar pits can trap animals that wander into them, creating the potential for fossil preservation. Although the fossil record from the Simi Valley tar pits is far smaller and less studied than that of La Brea, they serve as a reminder of the region’s rich geological history and its connection to ancient ecosystems.
The broader geology of Southern California continues to reveal clues about prehistoric life. Sedimentary rock formations throughout the region sometimes contain fossils of marine reptiles such as mosasaurs and plesiosaurs. These creatures lived in the ancient seas that once covered parts of the area during the Mesozoic Era. Although they are not dinosaurs in the strict scientific sense, they were formidable marine predators that shared the planet with dinosaurs and are often grouped with them in discussions of prehistoric life.
Moving forward in time to the Cenozoic Era—the age of mammals—the fossil record in Southern California becomes much richer and more detailed. The Ice Age tar pits, cave deposits, and river sediments throughout the region preserve a wide variety of mammals, birds, and plants. These fossils help scientists reconstruct ancient climates and ecosystems, revealing that Southern California once supported grasslands filled with large mammals and predators very different from those living there today.
For modern residents and visitors interested in prehistoric life, Southern California offers many educational opportunities. Museums throughout the region display fossils and reconstructions of dinosaurs and other ancient animals. Field trips, fossil digs, and educational programs help people learn about the deep history of the landscapes they inhabit.
In addition to genuine fossils and scientific exhibits, Southern California is also home to one of the most famous dinosaur-themed roadside attractions in the United States: the Cabazon Dinosaurs. Located near Cabazon along Interstate 10, these enormous dinosaur sculptures have become a beloved landmark for travelers driving between Los Angeles and Palm Springs. From Sun Valley, the site is roughly a two-hour drive east, making it a popular day-trip destination for families and tourists.
The Cabazon Dinosaurs consist primarily of two gigantic sculptures: Dinny the Dinosaur, an enormous Apatosaurus stretching more than 100 feet long, and Mr. Rex, a towering Tyrannosaurus rex. These massive concrete figures were originally built in the 1960s by sculptor and entrepreneur Claude Bell as a way to attract customers to his roadside restaurant and gift shop. Over time, the dinosaurs became iconic roadside attractions, drawing visitors who were fascinated by their size and whimsical design.
The Cabazon Dinosaurs achieved even greater fame after appearing in the 1985 comedy film Pee-wee’s Big Adventure starring Paul Reubens as the quirky character Pee-wee Herman. In the film, Pee-wee visits the giant dinosaurs during his cross-country adventure to recover his stolen bicycle. One memorable scene takes place inside the giant dinosaur sculpture, cementing the location’s place in pop-culture history. Since then, fans of the movie have frequently stopped at the Cabazon Dinosaurs to take photos and relive scenes from the film.
Today the attraction includes a dinosaur museum, gift shop, and additional sculptures that celebrate prehistoric life. While the Cabazon Dinosaurs are not connected to actual fossil discoveries in the region, they play an important role in sparking public interest in paleontology. For many visitors—especially children—they provide an exciting introduction to the world of dinosaurs and the deep history of life on Earth.
In conclusion, the prehistoric story of Southern California is both complex and fascinating. Although dinosaur fossils are less common in the region than in some other parts of North America, geological evidence shows that dinosaurs did inhabit parts of the area during the Cretaceous period. The region’s dynamic tectonic history and extensive marine environments have shaped the fossil record, leaving behind clues that scientists continue to study. Features such as the Simi Valley Tar Pits remind us that natural processes can preserve traces of ancient life, while world-famous attractions like the Cabazon Dinosaurs celebrate the enduring fascination people have with dinosaurs. From genuine fossils to roadside giants made famous in Pee-wee’s Big Adventure, Southern California offers a unique blend of science, history, and pop culture that keeps the age of dinosaurs alive in the modern imagination.