Last updated: October 30, 2022
Verified by: AZ Animals Staff
© Orla/Shutterstock.com

Dinosaurs Scientific Classification


Read our Complete Guide to Classification of Animals.

Dinosaurs Conservation Status

Dinosaurs Locations

Dinosaurs Facts

Other dinosaurs
Group Behavior
  • Solitary/Group

Dinosaurs Physical Characteristics

  • Brown
  • Grey
  • Red
  • White
  • Gold
  • Tan
  • Albino
  • Green
  • Dark Brown
  • Light Grey
  • Dark Grey
  • White-Brown
  • Multi-colored
  • Black-Brown
Skin Type

This post may contain affiliate links to our partners like Chewy, Amazon, and others. Purchasing through these helps us further the A-Z Animals mission to educate about the world's species..

View all of the Dinosaurs images!


Dinosaurs are a large, extinct group of reptiles that lived during the Triassic Period roughly 240 million years ago. The large variations allows for them to survive Earth’s harsh environments because all the continents were still together. It is possible that they experienced continental drifting before they mysteriously disappeared 65 million years ago at the end of the Cretaceous Period.

Description & Size

Variety of Dinosaurs
The diverse group of dinosaurs was all vertebrates with textured skin, and they were grouped into avian dinosaurs and non-avian dinosaurs.


These creatures ranged in size. The smallest, Epidexipteryx hui which reached only 17.5 inches in height. The largest dinosaur, the Argentinosaurus, reached up to 120 feet and easily weighed 100 tons.

This diverse group were all vertebrates with textured skin. Groupings divide them into avian dinosaurs and non-avian dinosaurs. The avian variety are those who fly and possess wings, and all others are non-avian.

Dinosaurs ranged in size, appearance, and habits depending on the species that they were. There are over 700 valid species of dinosaur so far.

Diet – What Did Dinosaurs Eat?

Dinosaurs were classified as either carnivores, herbivores, or omnivores. Those such as the T-Rex were carnivores and likely preyed on other dinosaurs as a meal. Whereas the Brachiosaurus was an herbivore that lived off vegetation.

Articles Mentioning Dinosaurs

See all of our entertaining and insightful animal articles.

Some ate both plants and meat in their diet because their digestive tract could digest both types of foods and absorb the nutrients. Herbivores likely ate twigs and seeds from plants to grind down on the material for better digestion due to their flat teeth.

Their diverse diet is species specific and scientist determine it based on teeth structures. Carnivores had large and defined canines, whereas herbivores have flat, squared-off teeth. Omnivores have a mixture of both, but the canines were less defined than carnivorous dinosaurs.

Habitat – When and Where It lived

Dinosaurs inhabited all of the continents during the Triassic Period of the Mesozoic Era 230 years ago. The continents were still together during this time. Their fossils have also been found throughout the world. This indicates they roamed the entire Earth, however some species were more plentiful in certain areas than others.

All the continents were arranged into one supercontinent known as Pangea. It slowly broke apart after they had been inhabiting it for 165 million years. The habitat ranged from dry desert lands where the Troodon and Allosaurus dinosaurs inhabited, to the forests and richly vegetated areas was the Lambeosaurus.

Others, such as the Plesiosaurs, lived in the ocean. There were both terrestrial and aquatic species that roamed the various forests, deserts, and oceans of the world.

Threats And Predators

A dinosaur’s main threat was other dinosaurs, lack of food and resources, along with natural disasters. Some had a predatory nature and would hunt other dinosaurs for food, whereas some species would consume vegetation and rely on the surrounding environment to provide food from them. If too many carnivores were in one area, their food sources would quickly deplete faster than their prey could reproduce.

Discoveries and Fossils – Where It was Found

The first dinosaur fossil was discovered in 1676 called the Megalosaurus in England. The fossil was not given a name until scientists started studying them in the 1820s. The British fossil was discovered by Robert Plot and named by William Buckland.

Over the years paleontologists and scientists have been discovering plenty of well-preserved fossils that give us better insight into how these creatures lived and looked. So far paleontologists have discovered over 700 different dinosaur species, however, there are believed to be many more awaiting discovery.

Extinction – When Did It Die Out?

Dinosaurs went extinct 65 million years ago at the end of the Cretaceous Period after roaming the earth for 165 million years. The reason behind their extinction is still a mystery, but scientists have formed various scenarios that could be the reason for their extinction, such as an asteroid strike known as the Paleogene mass extinction. Other theories include weakened ecosystems, continental drift, carbon or sulfur dioxide poisoning, or perhaps extreme climate change.

The most agreeable theory many scientists believe is from asteroid impact which caused the catastrophic global impact. The asteroid could have affected the earth’s climate as one of the long-term effects of an asteroid impact is changes in the atmosphere and a planet’s climate.

Similar Animals to The Dinosaur

Surprisingly, there are still some animals that roam the earth today that are either closely related to them or have a striking resemblance. The similarities are from the shared DNA and similar bone structure as discovered by scientists and researchers.

These are similar animals to the dinosaur:

  • Chickens- Both dinosaurs and chickens share similar DNA along with a similar bone structure.
  • Crocodiles- They come from the same ancestor as dinosaurs, which are reptiles.
  • Turtles- Scientists believed turtles coexisted with dinosaurs.
  • Lizards- Both dinosaurs and lizards are reptiles with four limbs, lay eggs, and live on land.
  • Sharks- The megalodon was a prehistoric shark that likely live with dinosaurs and is a descendant of modern sharks.

View all 90 animals that start with D

About the Author

I am a big animal lover that not only enjoys owning and getting to care for them, but also to write about them! I own many fish, along with shrimp, hamsters and a docile tarantula. Writing has become my passion and I am grateful to be able to write about the animals I love so dearly so that I can share my knowledge and expertise in the articles I write.

Dinosaurs FAQs (Frequently Asked Questions) 

When were dinosaurs alive?

Dinosaurs were alive 230 million years ago during the late Triassic Period of the Mesozoic Era.

How big were dinosaurs?

Dinosaurs ranged in size from as small as 17.5 inches to as large as 120 feet depending on the species of dinosaur. The smallest dinosaur was the Epidexipteryx hui and the largest was the Argentinosaurus.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.

  1. Wikipedia , Available here: https://en.wikipedia.org/wiki/Dinosaur
  2. Student share , Available here: https://studentshare.org/biology/1459178-dinosaurs-in-science
  3. Science focus , Available here: https://www.sciencefocus.com/nature/dinosaurs/

Newly Added Animals

A Black Mouth Cur
Black Mouth Cur

From the dog's description in the book, it is believed that Old Yeller was actually a Black Mouth Cur.

A Eryops

Unlike modern amphibians, Eryops had a well-developed rib cage

A Haikouichthys

Haikouichthys was the first animal to develop a well-defined head

Most Recently Updated Animals

A Black Mouth Cur
Black Mouth Cur

From the dog's description in the book, it is believed that Old Yeller was actually a Black Mouth Cur.

A Eryops

Unlike modern amphibians, Eryops had a well-developed rib cage

A Scottish Deerhound
Scottish Deerhound

"The Royal Dog of Scotland"