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Are Crocodiles Dinosaurs?

With their massive, scaly bodies and enormous, powerful jaws, crocodiles certainly have some similarities with dinosaurs. In fact, the fossil record is full of crocodiles, many of which look more or less exactly like the ones we see today. They’ve lived on this planet virtually unchanged since the time of the dinosaurs, and the comparisons to dinosaurs are common. After all, they’re giant, ancient reptiles, just like the dinosaurs were. However, are crocodiles dinosaurs or are they just descendants of dinosaurs?

Are Crocodiles Dinosaurs?

No, crocodiles are not dinosaurs. Crocodiles are reptiles. Even though they almost certainly have a common ancestor with dinosaurs, but they are a separate branch of the reptile family tree.

Crocodiles co-existed with dinosaurs, and the modern crocodile species have changed very little over the eons that have passed since the extinction of the dinosaurs. Both crocodiles and dinosaurs evolved from an ancient group of reptiles called the archosaurs.

What are Crocodiles?

Crocodiles are reptiles. They’re large, cold- blooded predators that have adapted to live mainly in the water, only coming on land to bask in the sun, lay their eggs, and digest their food. They’re one of the most successful groups of animals to ever evolve, and today they’re the largest reptiles in the world.

Crocodiles are distinguished by long, relatively narrow snouts, incredibly powerful jaws, and large, spiky teeth. They have short, stubby legs with webbed feet and large, powerful tails that propel them in the water. All surviving crocodile species are carnivores, with most feeding primarily on fish and small animals, and a few of the largest species hunting large mammals.

Were there prehistoric Crocodiles?

Crocodiles weren’t always the aquatic creatures we see today. While crocodiles like modern crocs have existed since the time of the dinosaurs, crocodilians were once a much more diverse group. At one time, there were both large (30 and 40 feet long) aquatic crocodiles that, like a supersized Nile crocodile, hunted dinosaurs that came to the waters edge for a drink, and there were much smaller land-dwelling crocodiles that looked quite different.

These land-crocs had long legs that stuck straight down from their bodies, and some of them were no bigger than a medium-sized dog. Ancient crocodiles were nearly as diverse as their dinosaur cousins, inhabiting all kinds of environments and coming in all shapes and sizes.

These land crocodiles outlasted their dinosaur counterparts, surviving to terrorize the mammals that began to take over after the extinction of the dinosaurs. However, this didn’t last long, as the warm-blooded mammals were much better suited to the environment they found themselves in, and soon only the massive, largely aquatic ancestors of modern crocodiles remained.

What were Archosaurs?

Archosaurs were the ancestors of crocodiles, pterosaurs, and dinosaurs. There were several species of archosaur which looked very much like modern crocodiles, but there were also plenty that didn’t. By the early Triassic period, when the first dinosaurs were just beginning to appear, the archosaurs were the dominant group of animals, the “ruling reptiles,” as paleontologists often refer to them.

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Archosaurs had evolved into many different animals living in every possible environment all over the world. Over time, most of them died out while the surviving species evolved into dinosaurs, crocodiles, and pterosaurs.

Are there any living dinosaurs today?

Crocodiles may not be dinosaurs, but some of their closest living relatives are: birds. It’s commonly believed that birds evolved from dinosaurs, but this isn’t really accurate. Birds did not evolve from dinosaurs, birds are dinosaurs. Dinosaurs that we would recognize as birds had already evolved by the end of the Cretaceous period and they were the only group of dinosaurs to survive the massive extinction event 65 million years ago.

Many scientists argue that crocodiles are actually more closely related to birds than they are to other reptiles, since birds share a common ancestor with crocodiles. In fact, this relationship highlights one of the major differences that separates crocodiles from dinosaurs: many dinosaurs, including all birds, were/are warm blooded, meaning they can maintain their own body temperature like we can.

Crocodiles are cold-blooded, which means they rely on their environment to regulate their temperature. If they need to warm up, they bask in the sun, and if they need to cool off, they dive underwater.

Did Crocodiles eat dinosaurs?

Some ancient crocodiles were certainly large enough to eat dinosaurs. Deinosuchus and Sarcosuchus were gigantic crocodiles living during the cretaceous period that would’ve been capable of killing and eating many of the dinosaurs they shared their habitat with.

Conversely, it’s also likely that many of the smaller prehistoric crocodile species were preyed upon by larger carnivorous dinosaurs.

How big do Crocodiles get?

The largest living crocodiles are the Saltwater Crocodile, also called the Estuarine crocodile, is the largest living crocodile, and has the strongest bite force of any living animal. These huge predators can reach close to 20 feet in length and weigh 2,200 pounds. Their bite has been measured at 3,690 pounds of force, and it’s estimated that larger specimens can probably bite with over 7,000 pounds of force. For reference, it’s estimated that a full-grown T. Rex had a bite force of about 8,000 pounds.

While saltwater crocs are huge, their prehistoric ancestors grew even bigger. Deinosuchus is estimated to have routinely reached 30 feet in length, with 40 foot lengths common for the largest adults, who would’ve weighed in at about 11,000 pounds.


Crocodiles are not dinosaurs, but they are closely related, and they share a common ancestor. Crocodiles have their own fascinating fossil history, and we’ll never truly know just how diverse in size and lifestyle the prehistoric crocodiles truly were. They shared their world with dinosaurs just as modern crocodiles share their world with birds, the true living dinosaurs of our world.

While birds are the true living dinosaurs, it’s crocodiles who look the part, and both of them have ancient lineages that can be traced back millions of years. They’re all descended from the archosaurs, ancient reptiles that gave rise to crocodiles, dinosaurs, and pterosaurs. They may not be dinosaurs, but crocodiles do give us a glimpse into the world of the giant reptiles that once ruled the planet.

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