How long were dinosaurs on earth? On this page we’ll find out how long the ‘age of the dinosaurs’ lasted. We’ll find out when the first dinosaurs appeared, and when dinosaurs went extinct.

We’ll also take a look at the geological time periods in which dinosaurs inhabited Earth. These are periods of time based on layers of rock. They include the Triassic, Jurassic and Cretaceous periods.

At the end of the page, you’ll find a list of amazing facts about how long dinosaurs were on Earth and the immense timespans involved.

This page is part of a series of articles about dinosaurs. If you want to become an expert on the subject, visit our main Dinosaur Facts Page!

How Long Were Dinosaurs On Earth?

Dinosaurs were on Earth for between 165 and 177 million years.

They first appeared between 243 and 231 million years ago, during the Triassic period. (We’ll find out more about the Triassic and other geological periods further down the page).

Dinosaurs became extinct around 66 million years ago. This means that they were on Earth for far longer than they’ve been extinct.

Dinosaurs were extremely successful, especially when you consider that modern humans (Homo sapiens) have only been around for 200,000 years!

Today, many scientists now regard birds to be dinosaurs! This is because during the Jurassic period a branch of dinosaurs began to evolve into birds.

Therefore, when we talk about ‘dinosaurs’ on this page, we’re referring to ‘non-avian’ dinosaurs – i.e. all those dinosaurs that didn’t evolve into birds.

Let’s Talk Numbers!

One million in figures is a one followed by SIX zeros, e.g. 1,000,000. Therefore, in figures, dinosaurs were on Earth for as long as 177,000,000 years.

That’s a long time!

While we’re talking big numbers, you may be interested to learn that Earth formed around 4.54 billion years ago. One billion in figures is a one followed by NINE zeros, or: 1,000,000,000.

Therefore, in figures, Earth formed 4,540,000,000 years ago.

Life began to appear around 3.5 billion (3,500,000,000) years ago

So, in the big scheme of things, even dinosaurs, who were on Earth for 177,000,000 years, are relative newcomers!

When Did Dinosaurs Appear on Earth?

As we’ve seen, dinosaurs first appeared on Earth between 243 and 231 million years ago. They evolved from a group of reptiles called Archosaurs.

This was during the Triassic period, which is part of what is known as the ‘geological timescale’.

The Geological Timescale

In the geological timescale, periods of time correspond to layers of rock. For example, the Triassic period refers to the time during which the rock in the Triassic layer was formed.

Just as days are divided into hours and minutes, etc., so are the units of the geological timescale. An era is divided into periods, which are themselves divided into epochs.

You can find out more about the geological timescale and the age of the dinosaurs here: Dinosaur Periods.

How Long Were Dinosaurs On Earth: The Mesozoic Era

Dinosaurs were around during the Mesozoic era, which is divided into 3 periods: the Triassic, Jurassic and Cretaceous periods.

Dinosaurs appeared on Earth midway through the Triassic period. They became the dominant land animals near the beginning of the Jurassic period. They were on Earth right up to the end of the Cretaceous period.

At the end of the Cretaceous period, something happened that caused the extinction of not just the dinosaurs, but of 75% of all of the species on Earth!

Scientists now think that the most likely explanation for the extinction of the dinosaurs is that Earth was hit by a large asteroid.

You can find out more about the extinction of the dinosaurs here: How Big Was The Asteroid That Killed The Dinosaurs?

Are Dinosaurs Really Extinct?

Strictly speaking, dinosaurs still exist on Earth. As we’ve seen in many of our dinosaur pages, scientists now consider birds to be dinosaurs.

This is because animals are grouped in ‘branches’. Because a group of dinosaurs ‘branched off’ and evolved into birds, they are still considered to be dinosaurs.

Therefore, instead of dying out at the end of the Cretaceous periods, dinosaurs are still alive and well, and living in your back yard!

How Long Were Dinosaurs On Earth – 10 Facts

Dinosaurs were on Earth for between 165 and 77 million years. Dinosaurs first appeared between 243 and 231 million years ago This was during the Triassic period Dinosaurs evolved from a group of reptiles called Archosaurs The Triassic – and other periods in the geological timescale – correspond to layers of rock. Earth formed around 4.54 billion years ago. (That’s 4,540,000,000 years ago in figures.) Life appeared on Earth around 3.5 billion (3,500,000,000) years ago. Homo sapiens (humans) have been on Earth for around 200,000 years. Many scientists now regard birds to be dinosaurs – therefore dinosaurs are still on Earth! All non-avian dinosaurs became extinct at the end of the Cretaceous period, around 66 million years ago.

How Long Were Dinosaurs On Earth – Conclusion7

In this article we’ve found out that Dinosaurs were on Earth for between 165 and 77 million years. We’ve also found out a little about the geological timescale, and how many scientists think that dinosaurs still exist in the form of birds.

We hope that you have enjoyed learning about how long dinosaurs were on Earth. IF you want to learn more about dinosaurs and the Mesozoic Era, there are plenty more Active Wild articles for you to enjoy:

Become a dinosaur expert – visit our main Dinosaur Facts Page.

Learn the names of many common (and not so common) dinosaurs here: List of Dinosaurs with Pictures.

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