Dinosaur Time Periods


Dinosaurs roamed the Earth for over 180 million years, leaving an indelible mark on our planet's history. This vast span of time is divided into three main periods: the Triassic, Jurassic, and Cretaceous. 

Each period had its own unique characteristics, including distinct dinosaur species, climate patterns, and vegetation.

Close-up of a dinosaur fossil skull representing the scientific study of dinosaurs from different time periods.

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A Triassic period landscape with Coelophysis dinosaurs in a hot and dry climate.

Triassic Period 

(252 to 201 million years ago)
The Triassic Period was the first chapter in the age of dinosaurs. It followed the Permian-Triassic extinction event, the largest mass extinction in Earth's history.
  • The climate was generally hot and dry, with seasonal monsoons
  • Pangaea began to break apart into separate continents
  • The first true dinosaurs emerged, including small bipedal predators and large quadrupedal herbivores
  • Other reptiles like pterosaurs and crocodylomorphs also appeared
  • Conifer plants were dominant, along with ferns and horsetails

During the Triassic Period (252 to 201 million years ago), the first dinosaurs began to appear, having evolved from reptiles called Archosaurs. The supercontinent Pangaea dominated the Earth, and the climate was generally hot and dry. Iconic dinosaurs of the Triassic include Coelophysis and Plateosaurus.

Action scene depicting a Velociraptor hunting a Protoceratops in the Jurassic period.

Jurassic Period 

(201 to 145 million years ago)
During the Jurassic Period, dinosaurs greatly diversified and became the dominant land vertebrates. Many iconic dinosaur species evolved during this time.
  • The climate was warm and humid, with no polar ice caps
  • Pangaea continued to separate into the northern Laurasia and southern Gondwana
  • Dinosaurs like Stegosaurus, Brachiosaurus, and Allosaurus emerged
  • The first birds evolved from small feathered dinosaurs
  • Conifers were the dominant plants, but ferns, cycads and ginkgoes were also common
Jurassic period scene featuring Brachiosaurus and Stegosaurus dinosaurs in a lush, warm environment.

Tyrannosaur Rex

The T. Rex is one of the most iconic dinosaurs for most people

Cretaceous Period 

(145 to 66 million years ago)

The Cretaceous was the final and longest period in the age of dinosaurs. It ended with the Cretaceous-Paleogene extinction event, which wiped out the non-avian dinosaurs.

  • The climate was warm, but cooled approaching the end of the period
  • The continents continued to drift toward their modern positions
  • Well-known dinosaurs like Tyrannosaurus rex, Triceratops, and Velociraptor appeared
  • Flowering plants emerged and diversified
  • At the end of the Cretaceous, a massive asteroid impact and volcanic eruptions caused the extinction of the dinosaurs (except birds)
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Frequently Asked Questions about Dino Time Periods

The three main dinosaur time periods are the Triassic, Jurassic, and Cretaceous periods. These periods span from approximately 252 million years ago to 66 million years ago.

The Triassic Period lasted from 252 to 201 million years ago (51 million years), the Jurassic Period lasted from 201 to 145 million years ago (56 million years), and the Cretaceous Period lasted from 145 to 66 million years ago (79 million years).

At the end of the Triassic Period, there was a mass extinction event that wiped out many species, including some early dinosaur groups. However, dinosaurs survived and thrived during the Jurassic and Cretaceous periods. At the end of the Cretaceous Period, a massive asteroid impact and volcanic eruptions caused the extinction of non-avian dinosaurs.

No, different dinosaur species lived during each period, and many species were specific to a particular period. Some dinosaur groups, such as sauropods and theropods, existed throughout all three periods but were represented by different species in each period.

The climate and environment varied between the Triassic, Jurassic, and Cretaceous periods. The Triassic was generally hot and dry, the Jurassic was warm and humid, and the Cretaceous had a warm climate that cooled towards the end of the period. The distribution of continents and oceans also changed throughout these periods due to plate tectonics.

Many other animals coexisted with dinosaurs during the Triassic, Jurassic, and Cretaceous periods, including marine reptiles like plesiosaurs and ichthyosaurs, flying reptiles called pterosaurs, early mammals, crocodilians, turtles, fish, and invertebrates.

Scientists study dinosaurs by examining fossils, which are the preserved remains or traces of ancient life. Paleontologists excavate, prepare, and analyze dinosaur fossils, including bones, teeth, eggs, and footprints. They also study the rock layers and geological context in which fossils are found to learn about the environment and climate of the time.