Small and large lizards are found wandering in almost every continent on the planet today. Their reptilian bodies can resemble that of a dinosaur, and the literal meaning of the word dinosaur is terrible lizard. So, are lizards dinosaurs, or are they related to dinosaurs?
Lizards are not dinosaurs. Though they seem to have similar characteristics to the creatures in Jurassic Park, they are not closely related to dinosaurs at all. An animal’s ancestry and body characteristics can determine whether or not it is a relative to the dinosaur family.
Read more to figure out why lizards are not related to dinosaurs, but how birds and crocodiles are. There are discoveries and research that explain why certain animals are or are not classified as modern-day dinosaurs.
What is a Lizard?
Unless you live in Antarctica, you have probably seen a lizard. However, you have probably never seen a dinosaur. That said, you probably have seen a relative of the dinosaur but more on that later.
Different kinds of lizards have different characteristics, which is why there are lizards in almost every part of the world. Scientists have discovered evidence that the lizard species has been on the earth for over 200 million years.
There are several different types of lizards among the species such as leopard geckos, tegus, chameleons, Komodo dragons, and more. In fact, there are over 4600 different types of lizards on the planet.
Animals are categorized into different groups called amphibians, mammals, reptiles, and insects. The animal’s category depends on what they eat, where they live, what their body is like (if they are warm or cold-blooded), and how they reproduce. Lizards are considered reptiles because they are cold-blooded, lay eggs, and are covered in scales.
Lizards vary in size. The smallest lizard was recently discovered in 2021 and is called a nano chameleon. It is normally 0.5-0.7 inches long, including the length of its tail. It is small enough to stand on the tip of your finger.
The largest type of lizard in the world is the Komodo dragon, which typically weighs about 154 lbs. The average length for a male Komodo dragon is 8.5 feet for a male and 7.5 feet for a female.
What is a Dinosaur?
There is more to dinosaurs than the little toy action figures you see children play with. Luckily, the illustrators of the well-known movies Jurassic Park and Jurassic World had big imaginations and were able to give us an idea of how dinosaurs lived and what they looked like. The facts about dinosaurs go beyond what we can learn from kid’s books, toys, and dinosaur movies.
The word dinosaur came from the Greek words deinos and sauros. Deinos means terrible and sauros means lizard. This word was created in 1841 by Sir Richard Owen, a paleontologist and biologist who studied dinosaur fossils. Owen’s word for these extinct reptiles could have caused the confusion about lizards being dinosaurs.
Before the asteroids collided with the earth and killed most animal life, there was a type of dinosaur called a theropod. Therapods came in different shapes and sizes. They were reptilian but similar to birds. They could have even had feathers and other bird-like characteristics, which I will talk more about later.
Some of these therapods were able to survive the asteroid massacre, and they evolved to become more similar to birds. Some of the bird fossils that were found to be closely related to dinosaurs are the sinornis santensis and vegavis aiai.
The brachiosaurus, stegosaurus, triceratops, and more are all among Earth’s ancient dinosaurs. Even though dinosaurs were on the earth 66 to 245 million years ago, the term “dinosaur” has only been around for 181 years.
Dinosaurs and Lizards Both Lay Eggs
Dinosaurs are hatched from eggs, just like lizards, snakes, and fish are. They are classified as reptiles and they live on land, not in water. So, even the ancient creatures that lived in the sea and looked like dinosaurs were not considered dinosaurs because they did not have any of the same ancestors. Examples of the creatures that lived in the sea long ago are the ichthyosaurs and plesiosaurus. (Source)
Several different fossils have been discovered since and there are certain standards that make an animal a dinosaur. Paleontologists have decided a pterodactyl is not a dinosaur but is actually a flying reptile. Whether an animal is defined as a dinosaur depends on whether it has a common ancestor with the dinosaurs.
Paleontologists have found indications within fossils that some dinosaurs were endothermic, meaning they were warm-blooded. This makes them different from the reptiles of today. Dinosaurs also differ in the way their legs protrude from their body. While lizards’ legs protrude from the side of their bodies and are bent at the knees, dinosaurs’ legs were straight. Dinosaurs walked more similarly to chickens than lizards and other reptiles. (Source)
A Lizard’s Relation to Dinosaurs
When the appearances are compared, lizards look very similar to many dinosaurs. Why couldn’t a Mexican mole lizard, Lazarus lizard, or Gila monster be related to a dinosaur? Like lizards, dinosaurs are reptilian, as is the case with animals like turtles, iguanas, snakes, geckos, and more. None of these modern-day reptiles are considered dinosaurs except for birds. By most paleontologists, birds are considered modern-day dinosaurs. (Source)
Dinosaurs were not the only type of reptiles on the earth during their time. There were other reptilian animals, but there are certain details about their physical bodies that make them a different type of reptile.
Think about the way a dinosaur walks. Now think about the way lizards walk. Dinosaurs and lizards walk very differently. A dinosaur walked similarly to a modern-day chicken with its legs straight down. Most had 3 big claws. A dinosaur’s neck also moved more as a chicken does. Dinosaurs could stand upright and run fast.
Lizards Are Built Different Than Dinosaurs
A lizard moves more like a snake with legs and in a side-to-side motion. Their body formation doesn’t allow them to run as fast as a dinosaur would have been able to. This is because their hip bones are much different. Lizards do not have a hole in their hip socket and dinosaurs did. Therefore, lizards are not dinosaurs.
There is one unique animal on the earth that has ancient origins. It is only living in one country in the world– New Zealand. The time period of these animals’ extinct relatives dates back to the time of the dinosaurs. It is closely related to a reptile that lived during that age. This animal can get confused with a lizard, but it is actually not a lizard. It has several physical differences. Because of this animal’s ancient origin, some professionals refer to it as a “modern fossil.” (Source)
The name of this special reptile is the “tuatara.” The Tuatara is the only relative left of the Sphenodontia kind, which lived during the time of the dinosaurs. It was 60 million years ago that the rest of the Sphenodontia species went extinct.
What makes them different from lizards is that they don’t have external ears, they are nocturnal, and they don’t love the heat as much as lizards do.
As far as what the tuatara likes to eat, it is similar to the lizard species. Tuataras like to eat insects such as spiders, mealworms, and millipedes. However, they also eat lizards.
Though the ancestors of the Tuatara live during the time of the dinosaurs, the Tuatara like the lizard is not a dinosaur species.
Dinosaurs and Crocodiles’ Relation to Dinosaurs
A lizard looks even more like a crocodile than a dinosaur, and a crocodile looks more like a dinosaur than a lizard. But a crocodile’s legs protrude from its side, unlike dinosaur legs. So, are crocodiles dinosaurs? Are alligators dinosaurs?
Crocodiles are the second-closest related species to dinosaurs. Crocodiles do share a common ancestor with dinosaurs, unlike lizards. This ancestor group is called archosaurs. Birds are also related to archosaurs, so this means that crocodiles and birds are related. (Source)
Although crocodiles and alligators have different body structures than dinosaurs, they are related to dinosaurs because they share a common ancestor.
Unfortunately, the cute little lizards we see crawling across the hiking trails, at the pet store, and under our houses are not relatives to the monsters in Jurassic Park. Their legs are simply not the same, and their ancestors also lived during the time of the dinosaurs.
Birds’ Relation to Dinosaurs
Flamingos, toucans, emu’s, and even seagulls are closer related to dinosaurs than lizards are.
A fossil of the animal called the archeopteryx led to our knowledge that birds are related to dinosaurs because this fossil showed both reptilian and bird-like characteristics. It appeared to have legs and wings. Illustrators have drawn it to look like a small feathered dragon.
There is no evidence that birds evolved from dinosaurs, but there is evidence that birds existed during the age of dinosaurs, and they are one of the only species that can date back to that time period. Reptiles and sea creatures were also on the earth during that time.
Paleontologists do everything they can to examine fossils and compare them to other creatures who lived during their time and to modern-day creatures. It can be extremely difficult to pinpoint when a creature lived, what it ate, what it looked like, and where it came from. Luckily, experienced paleontologists are discovering new information every day.
Certain DNA and molecules can be found in fossils which helps the paleontologists know what the animals could be related to. It would uncommonly be assumed that today’s poultry could be related to a monster of the past– the T-Rex.
Chickens Are More Closely Related To Dinosaurs Than Lizards Are
It was once found that the ostrich and chicken are related to the terrifying, meat-eating dinosaur, the Tyrannosaurus Rex. The graphic designers of Jurassic Park and Jurassic World were able to analyze the movement of birds in order to create realistic dinosaurs. (Source)
Crocodiles were also found to be related to the dinosaur.
Though lizards may appear more similar to the velociraptors and Tyrannosaurus Rex in Jurassic Park, your neighbor’s chickens and the hummingbird outside your window are more related to the dinosaurs.
More discoveries and theories are coming to fruition every day. There are already several different theories about dinosaurs and their descendants, but there are more to come. Scientists and paleontologists are still studying different fossils. They are working to classify each new discovery into the category it best fits in.