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Digital rendering of the Earth during the Cretaceous Period featuring an Ankylosaurus, Brachiosaurus, and other Dinosaurs.
Did you know that dinosaurs once lived in California? Millions of years ago, our state was home to some fascinating prehistoric creatures! In this post, we take a step back in time to explore California’s prehistoric past with some mind-blowing dinosaur facts for kids!
General Dinosaur Facts for Kids
🦖 Dinosaurs first evolved roughly 252 million years ago during the Mesozoic Era.
🦴 A fossil is the preserved remains or traces of a plant or animal that has turned into rock.
🥚 Dinosaur fossils can be bones, footprints, or even eggs preserved in the ground for millions of years.
🔬 Scientists who study fossils to learn about dinosaurs are called Paleontologists.
🦕 Around 700 different species of dinosaurs have been discovered to date.
🦅 Birds are dinosaurs. Yup. All birds evolved from small, feathered dinosaurs millions of years ago.
☄️ All non-flying dinosaurs went extinct about 66 million years ago, likely due to a giant asteroid hitting Earth.
Join us for Dino Trax: Dinosaur Train Days!
May 31 & June 1, 2025
Want to keep the prehistoric adventure going? Don’t miss Dino Trax: Dinosaur Train Days, a one-of-a-kind event where dinosaurs and trains come together for a roaring good time! Climb aboard our dinosaur-themed train exhibits and dive into hands-on activities that are perfect for kids of all ages.
Get your tickets today, and join us for a day full of discovery, hands-on fun, and dino-mite adventures at the Children’s Museum of Sonoma County!
Dinosaurs Lived in California 75 Million Years Ago
Digital rendering of Earth during the Cretaceous Period featuring an Ankylosaurus, Brachiosaurus, Velociraptor, and other Dinosaurs.
Fossils found throughout the state suggest dinosaurs lived in California between 75 million to 66 million years ago during the Late Cretaceous Period.
To understand just how long ago that was, let’s zoom out a bit!
The Mesozoic Era: “The Age of Dinosaurs”
Dinosaurs roamed the Earth between 252 million to 66 million years ago, in a time known as the Mesozoic Era, or “The Age of Dinosaurs.” The Mesozoic Era is divided into three periods:
- Triassic Period (252 – 201 million years ago): This was the dawn of the dinosaurs! It’s when the very first dinosaurs started to evolve.
- Jurassic Period (201 – 145 million years ago): During this time period, giant plant-eating dinosaurs like Stegosaurus, as well as fierce meat-eaters like Allosaurus roamed the Earth.
- Cretaceous Period (145 – 66 million years ago): This was when some of the most well-known dinosaurs lived, including Tyrannosaurus Rex and Triceratops.
Sadly, the Mesozoic Era ended with a mass-extinction event that wiped out over 70-80% of all the plants and animals on Earth, including all the non-flying dinosaurs. Scientists believe this was most likely caused by a giant asteroid, roughly 6 miles wide, that crashed into Earth near the Yucatán Peninsula in Mexico.
California Has a State Dinosaur: Augustynolophus Morrisi (Auggie!)
Augustynolophus morrisi ”Auggie” California’s State Dinosaur – Source: Los Angeles County Museum of Natural History
That’s right, as of 2017, California has its very own official state dinosaur. Meet the Augustynolophus morrisi, but you can call him Auggie for short!
Auggie was a type of dino species called a Hadrosaur, also known as a duck-billed dinosaur. They got their name because the front of their mouth was wide and flat, kind of like a duck’s bill.
Scientists think Auggie was a plant-eater (herbivore) that lived in what is now central California around 72.1 million years ago
The First Dinosaur Fossil in California Was Found in 1939
A fossilized skeleton of a Hadrosaur dinosaur on display at a museum
Before the 1930s, scientists hadn’t found any dinosaur fossils in California. That made people think dinosaurs might never have lived here at all!
Can you guess what the first dinosaur fossil ever found in California was?
If you said Auggie, you are correct! The first dinosaur fossil discovered in California was the Augustynolophus in Fresno County in 1939.
Since the discovery of the first dino fossils in California, only a few other types of dinosaurs have been found here.
List of Dinosaurs that Lived in California:
Augustynolophus (“Auggie”)
Source: By Nobu Tamura, via Wikimedia
As we mentioned earlier, Augustynolophus was a type of Hadrosaur, meaning it had a mouth that looked like a duck bill. They grew up to 26 ft long, weighed around 6,600 lbs., and were herbivores, meaning they only ate leaves, grasses, and other plants.
Augustynolophus dinosaur fossils have only ever been found in California.
Aletopelta
Source: By Karkemish – Own work, CC BY 3.0, via Wikimedia
Aletopelta was a type of Nodosaur, which means its body was covered in strong bony plates and spikes. This was like having built-in armor to protect them from predators. Aletopelta were herbivores (plant-eaters) that grew up to 16 feet long and weighed 4,400 lbs.
Fossils of Aletopelta have been found in Carlsbad, California.
Albertosaurus
Source: By No machine-readable author provided, via Wikimedia
Albertosaurus dinosaurs are a type of Tyrannosauridae, making them close relatives to the Tyrannosaurus Rex. Albertosaurus were carnivores (meat-eaters), growing up to 26–30 feet in length and weighing 3,750–6,600 lbs. Even though they weren’t as big as T Rex, they were still a fierce predator with sharp teeth and strong legs for chasing after prey.
Although most have been found in Canada, some Albertosaurus fossils have also been found in Baja, California.
Very Few Dino Fossils Have Been Found in California
Digital rendering of a long-necked Plesiosaur: a marine reptile that lived in California during the Cretaceous period.
While scientists theorize that lots of different dinosaurs lived in California millions of years ago, very few fossils have been discovered here. This is because the majority of California’s land was covered by the ocean during the Mesozoic Era.
During the Age of Dinosaurs, California looked dramatically different from how it does today. Much of the state was covered by warm, shallow sea water. Because so much of California was underwater, the chances of dinosaur bones being preserved as fossils were much lower compared to places that were mostly land.
However, the ancient ocean that covered much of California was home to some incredible prehistoric sea creatures!
List of Prehistoric Sea Animals that Lived in California Oceans:
Shastasaurus S. Pacificus (“Mount Shasta Lizard”)
Source: By DiBgd – Own work, CC BY-SA 4.0, via Wikimedia
Shastasaurus (“Mount Shasta Lizard”) was a marine reptile that lived over 252 million years ago. As the name suggests, fossils of the Shastasaurus were found in Shasta County, California.
Californosaurus (“California Lizard”)
Source: By Nobu Tamura – Own work, CC BY 2.5, via Wikimedia
Californosaurus (“California Lizard”) lived 237 million years ago in the warm seawater that covered the majority of California. Fossils have been found in Plumas County and Shasta County, in Northern California.
Plesiosaurus
Source: By DiBgd – Own work, CC BY-SA 4.0, via Wikimedia
Plesiosaurs were large, swimming reptiles that lived over 200 million years ago. One of the most complete Plesiosaur fossils ever found was excavated from a low mountain range in western Fresno County, California, in 1937.
Mosasaurus
Source: By Creator: Dmitry Bogdanov – CC BY 3.0, via Wikimedia
Mosasaurs were aquatic reptiles that lived 82 million years ago in ocean habitats all over the world, including California. The first Mosasaurs fossil ever found in California was discovered in the San Joaquin Valley.
Plesiotylosaurus
Source: By Dmitry Bogdanov – CC BY-SA 3.0, via Wikimedia
Plesiotylosaurus was another marine reptile that lived in the warm seawaters of prehistoric California 72 million years ago. Fossils of Plesiotylosaurus have been discovered in the San Joaquin Valley, California.
Plotosaurus
Source: By Dmitry Bogdanov – CC BY 3.0, via Wikimedia
Plotosaurus was a fast-swimming marine reptile that lived about 70 million years ago, near the end of the Cretaceous period. The first fossils of Plotosaurus were discovered in the San Joaquin Valley, California.
From the Age of Dinosaurs to the Age of Discovery
Dinosaurs and ancient sea creatures may be long gone, but their fossils give us an exciting peek into what California was like millions of years ago. From learning about duck-billed dinosaurs to carnivorous ocean reptiles, these dinosaur facts for kids help bring science and history to life!
The Age of Dinosaurs is still full of mysteries, and there is a whole prehistoric world still buried in the rocks, just waiting for curious minds to find it. So keep exploring, asking questions, and maybe one day you’ll dig up the next big dinosaur discovery!
