Living Animals That Are Closely Related to Dinosaurs

The Mesozoic era, which includes the Triassic, Jurassic, and Cretaceous periods, contains 186 million years of dinosaur evolution. Despite this era being about 251 to 66 million years ago and dinosaurs being long extinct, there are quite a few living animals that are closely related to dinosaurs. Many of these animals look very similar to their prehistoric ancestors and remind us of how much of a force dinosaurs truly were.

Chickens: A Close Relative of the T. rex

Many birds share a family tree with dinosaurs, such as the cassowary, but the mighty Tyrannosaurus rex still walks among us today as a chicken. In truth, many modern birds descended from the tyrant lizard, but chickens are one of the closest living relatives. Paleontologists long speculated this relation due to their anatomical similarities. However, due to the wonders of modern science, paleontologists were able to get their hands on molecular collagen from a T. rex femur. When compared to the molecular structure of other animals, ostriches and chickens came up as the closest match.

Crocodiles: The Modern-Day Dinosaur

The Cretaceous period was at the tail end of the Mesozoic era, and we can date the earliest crocodile back to this time. Paleontologists believe that the earliest crocodilian ancestor was the Deinosuchus, which looks like a massive version of the crocodiles we know today. The Deinosuchus had more of an alligator-like snout but was about 35 to 45 feet long and weighed over 33,000 pounds. To put it into perspective, the most enormous crocodile ever recorded was only 20 feet long and weighed 2,370 pounds.

Lizards: Tiny and Terrible

One of the most common misconceptions about dinosaurs is that they’re lizards—while they may look similar, they come from entirely different animal groups. However, there is a connection, and the word dinosaur translates to “terrible lizard.” The first lizard was a reptile named Megachirella Wachtleri which originated in the middle of the Triassic period. All lizards and dinosaurs belong to the class Reptilia, but they branched off into two entirely different groups. However, they share similar genetic traits, such as egg-laying and general appearance. However, if you look at today’s lizards and compare them to dinosaurs, the positioning of their legs is very different.

Sea Turtles: A Close Cousin

The earliest ancestor of the sea turtle is the Eunotosaurus, which came about during the Permian period—the beginning of the Paleozoic era right after the end of the Mesozoic era. While the Eunotosaurus is not technically a dinosaur, they share very similar relatives, and both fall into the clade Sauropsida. Interestingly, the Eunotosaurus didn’t have a shell, and the mystery of where the shell came from still remains. However, we know they’re related as they have the same lack of intercostal muscles and a similar set of broad ribs.

Ultimately, this is just a very short list of the living animals that are closely related to dinosaurs, and there is so much more! Snakes, crabs, and sharks also share common ancestors, and with how much new information paleontologists are still finding out, who knows what interesting dino relatives we’ll find next!