When Did Dinosaurs Live?

Two long neck dinosaurs are walking on the ground in a beautiful sun rise background

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Our childhoods have never been complete without watching a Jurassic Park movie. However, one question we most usually thought of while watching animated dinosaurs series was how these dinosaurs live and how one can differentiate among these animal species.

In this article, we will share all you need to know about when did dinosaurs live and how you can differentiate them according to varying eras.

Non-bird dinosaurs used to live between approximately 245 and 66 million years ago, during the Mesozoic Era. This was the exact time before the first modern humans, Homo sapiens, probably millions of years ago.

The Triassic, Jurassic, and Cretaceous periods are the three-time eras used by scientists to categorize the Mesozoic Era. Here we will explain every era and its animal species in detail one by one.

How Long Did Dinosaurs Survive on Earth?

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Contrary to what many people believe, dinosaurs are a species of reptiles. They appeared about 250 million years ago, and 66 million years ago, they underwent mass extinction. These animal species were classified into avian and non avian dinosaurs. 

The only avian dinosaurs still alive are birds, but all other non avian dinosaurs underwent mass extinction. The largest animal to roam the Earth, dinosaurs dominated the vertebrate kingdom for the entirety of their existence. Dinosaurs existed were divided into three periods based on when they lived; the Triassic period, the Jurassic period, and the Cretaceous period. 

We will discuss these three periods and how each ended in detail below.

Triassic Period

The dinosaurs in the triassic period

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The Triassic Period dates back to some 201 to 205 million years ago. Following a catastrophic extinction event 250 million years ago that wiped out most of the planet’s species, many large animals emerged, including the pterosaurs, the world’s first flying vertebrates. 

Pangaea was the name of the landmass that covered most of the planet during the Triassic Period, and the majority of plants and animals had traits that were quite similar. When Pangaea began, it had no polar ice caps, and the desert covered a sizable portion. 

Around this time, the dinosaurs started to walk the Earth because the hot, dry climate created ideal circumstances for reptiles to flourish. The Coelophysis is one of the Triassic dinosaurs, a group of extinct animals that lived at that time. 

A giant spinosaurus and other dinosaurs beside the river

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The North Atlantic Ocean was created as a result of the extinction event of the Triassic period due to earthquakes and volcanic eruptions that split the continent in half. Despite everything we know about dinosaurs, their evolutionary roots remain a mystery. 

The earliest dinosaurs were thought to have been small, bipedal reptiles with small, gripping hands that were considered carnivorous dinosaurs. The smaller, bipedal Eoraptor and the bigger Herrerasaurus were instead the first real dinosaurs to be discovered in the fossil record. Dinosaurs had carved out a special place for themselves in the ecosystem by the late Triassic Period. 

They continued to take on various shapes of other species around the globe. However, their fortunes would soon alter due to another significant extinction event, which ended the period about 201 million years ago and may have been brought on by volcanic eruptions or a possible asteroid impact. Many of the first archosaurs were killed by this catastrophe. Still, dinosaurs survived and took over as the primary form of life during the Jurassic Period.

Jurassic Period

Illustration of small long neck dinosaurs in a forest

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As the Triassic period ended, the following period was known as the Jurassic period. This period dates back to some 201 to 145 million years ago. Climates warmed during this period, and Pangaea broke up into several continents. 

Dinosaurs would consequently significantly diversify throughout this time. By the late cretaceous period, it was the most widespread species in the world. Many dinosaur species were enormous in size and stature, in contrast to the earliest mammals. 

This crucial time in the evolution of dinosaurs saw the existence of some of the largest dinosaurs, the long-necked herbivorous Brachiosaurus, the armored Ankylosaurs, and the spiky Stegosaurus. Although it is evident that a mass extinction happened as the Triassic period ended, the reason why it happened is the subject of intense discussion among scientists. 

Some dinosaurs beside a lake

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In contrast to other huge animals going extinct, the dinosaurs lived and split into numerous subspecies. Dinosaurs evolved and used both continents as homes. A decline in temperature resulted from the enormous amount of carbon dioxide in the atmosphere, and an increase in rainfall caused the development of a new ocean. 

Animal habitat was created when flowering plants grew in places they had never before. The biggest dinosaurs, most of which were herbivorous dinosaurs that lived during this time. A few of the dinosaurs that survived were; Diplodocus, Apatosaurus, and Brachiosaurus.

Cretaceous Period

two brown dinosaurs with crests on the ground

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The Jurassic period was followed by the cretaceous period, which dates back to 66 million years ago. This was the final and greatest period of dinosaur dominance. During the Cretaceous period, dinosaurs evolved independently. 

The land was further divided into distinct landmasses situated in various places. Moreover, scientists discovered that despite a cool climate, woods still covered most of the world up to the poles. 

A wider variety of dinosaur species resulted from the autonomous evolution of the dinosaurs. Along with snakes, plants, insects, mammals, and even predators, other living things also underwent a period of diversification during this time.

How Did Dinosaurs Go Through Extinction?

Some dinosaurs of the apocalypse

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The dinosaur era came to an end as the Cretaceous Period ended. The last of the dinosaurs and around 75% of all plant and animal species on Earth perished in a giant asteroid collision about 66 million years ago. 

The asteroid unleashed massive ash into the atmosphere as it slammed into the planet with the force of 180 trillion tons of TNT, disrupting plant photosynthesis for years afterward. The majority of huge animals that weighed above 50 pounds quickly became extinct. 

The fossil of the dinosaur skull in the museum

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None of the scientists have yet figured out if the extinction of non-avian dinosaurs happened suddenly or gradually. Regardless, the only lineage to survive this time was that of the avian dinosaurs or birds. 

According to scientists, the world may have expanded due to a collision with an alien body, such as a comet or meteor, or from a series of volcanic eruptions that affected the world globally.

What are Modern Dinosaurs?

A stegosaurus is standing in the forest

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There is a widespread rumor that dinosaurs still exist, but most animals have two legs, not four legs. Theropods, a class of dinosaurs with two legs that included the tyrannosaurus rex and velociraptors, are the ancestors of chickens. 

This theory of common ancestor also prevails among reptiles like crocodiles. The visual impact of these enormous, scaly reptiles is reminiscent of old pictures of dinosaurs. Ostriches are among other uncommon land animals. In short, many more modern dinosaurs are connected to dinosaurs, and scientists could discover much more!

What were the Types of Dinosaurs that Lived on Planet Earth?

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According to the Paleobiology Database, there were 1,545 different species of dinosaurs that had been officially described as of 2021. Some of the most prominent ones are discussed below.


A Stegosaurus is standing on the cliff

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Dinosaurs from the Ornithischia order include beaked plant-eaters like Stegosaurus, dinosaurs with duckbills, horns like Triceratops, and armored dinosaurs like Ankylosaurus.


A group of sauropodomorpha dinosaurs in a dark background

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Dinosaurs belonging to the Sauropodomorpha family had long necks, pot-bellied bodies, small skulls, and limbs that resembled columns. Diplodocus and other sauropods are part of this group. Their smaller ancestors included titanosaurs, which were gigantic sauropods, and Chromogisaurus.


Cladogram of theropoda dinosaurs

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A group of dinosaurs known as Theropoda, some of which, like Chilesaurus diegosuarezi, modified their diet to become herbivorous or omnivorous, were meat-eaters. Tyrannosaurus rex and Velociraptor are examples of theropods, while birds are descended from little theropods.

Can Dinosaurs be Brought Back to Life?

Some animatronic dinosaurs in a park

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Could science bring back dinosaurs? In some ways, the answer is no. Scientists will never be able to rebuild dinosaurs as they once existed because DNA deteriorates with time. However, some researchers have suggested developing a modern-day dinosaur from a bird to recreate the extinct reptile that is still popular in folklore or, most accurately, in the popular imagination.

FAQs About When Did Dinosaurs Live

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Were Pterosaurs and Dinosaurs the Same?

Pterosaurs perished together with dinosaurs at the end of the Cretaceous Period after existing from the late Triassic Period. They are not dinosaurs since they can fly and have front limbs extending to the sides. They are actually a distant relative of a dinosaur.

Did Dinosaurs Use to Have Feathers like Birds?

Scientists had discovered that dinosaurs living a few thousand years before the cretaceous period or in the late Triassic period used to have feathers like modern-day animals.

Final Thoughts

several dinosaurs are walking in the water at night

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Various species of dinosaurs lived in the past, as evident from the dinosaur fossils discovered by scientists. These species went through extinction due to some unknown activity, or, you can say, a huge volcanic activity. However, humans believe that a past dinosaur evolved into a modern bird. If you want an amazing dinosaur now, look at them here! And if you want to know more about their lifespan you can read the blog Dinosaur Lifespan: How long did a dinosaur live

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