A herd of sauropod dinosaurs migrating during the dry season

Dinosaurs

Dinosaurs were the dominant land animals for 160 million years, making them one of the most successful groups of animals ever. The name dinosaur translates as 'terrible or wondrous lizards' and they certainly evolved in a diverse range of sizes and shapes, from the gigantic plant-eating sauropods to the quick meat-eating tyrannosaurs. They also sported an impressive array of body modifications including horns, scales and crests. So far, the remains of over 1,000 different dinosaur species have been identified from fossils though technically, birds are feathered dinosaurs, meaning dinosaurs aren't really extinct at all.

Did you know?
Dinosaurs were given their name by the English paleontologist Richard Owen in 1841.

Scientific name: Dinosauria

Rank: Superorder

Common names:

terrible, powerful, wondrous lizard

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Dinosaur size range

A graphic illustration comparing the size of dinosaurs with humans, from largest to smallest: Diplodocus (longest), Brachiosaur

A comparison of dinosaur size in relation to humans - from the 30m long Diplodocus to the 70cm tall Compsognathus.

Behaviours

Discover what these behaviours are and how different plants and animals use them.

Egg layer Egg layer
Oviparous animals lay eggs, inside which the young then develop before hatching occurs. Birds, reptiles, amphibians, fish, invertebrates and even some mammals (the monotremes) all lay eggs but they're of very different size and construction.

Additional data source: Animal Diversity Web

When they lived

Discover the other animals and plants that lived during the following geological time periods.

What their world was like

Desert Earth Desert Earth
A vast desert formed in Earth's prehistoric past when the supercontinent of Pangaea straddled the equator and stretched to the poles. Pangaea's position influenced ocean circulation patterns, and its huge size meant that there were vast areas where moist air from the oceans never penetrated.

What killed them

Cretaceous-Tertiary mass extinction Cretaceous-Tertiary mass extinction
The Cretaceous-Tertiary mass extinction - also known as the K/T extinction - is famed for the death of the dinosaurs. However, many other organisms perished at the end of the Cretaceous including the ammonites, many flowering plants and the last of the pterosaurs.

Fossil types

Learn more about the other animals and plants that also form these fossils.

Spirits of the ice forest - dinosaurs at the poles

By Dr Jo Wright

dern reptiles are cold blooded. However, a series of startling finds suggests there may have been dinosaurs living at the poles. What does this tell us about the possibility of warm-blooded dinosaurs. Dr Jo Wright investigates.

The idea that dinosaurs lived at the poles is based on remarkable finds made in Australia. There are two clues that Australia was once within the Antarctic Circle. Firstly, we can can determine at what latitude rocks formed from the orientation of magnetic particles within them. Secondly, evidence that the climate was seasonally cold comes from both plant fossils and sedimentary structures which form when the ground freezes.

A better picture

The fossil sites in Australia are remarkable because several different animals have been found, giving us a fuller picture of the palaeoenvironment (life in the area at the time).

At least some of the animals must have been year-round residents - Leaellynasaura were too small to have migrated hundreds of miles in and out every year. Leaellynasaura may have had a special adaptation for life in the polar regions.

Their skulls seem to have had especially large eye sockets. Their large eyes may have allowed them to see better in the continuous low light levels of the polar winter.

Hanging in there

Some of the fossil vertebrates at these sites are very important because some very primitive animals that had become extinct elsewhere seem to have survived here. Labyrinthodont amphibians, like Koolasuchus, were previously thought to have died out over 100 million years earlier. In this environment it occupied a crocodilian niche, as the climate was too cold for crocodiles.

The earliest known dinosaur found in polar palaeolaltitudes is called Cryolophosaurus (which means 'frozen crested reptile'), and was found in Antarctica. It is a meat-eating dinosaur but we do not know whether it migrated in during the summer months, or whether it lived there year round.

Dinosaurs from polar latitudes have also been found in Alaska, but they are very similar to those from further south and are probably just a migrant population.

The existence of dinosaurs at polar latitudes is significant. It means one of two things. Either dinosaurs had to hibernate or go into an inactive state in the polar winter. Or they had some way of maintaining a high body temperature - ie they were warm blooded.

Many people think that some, if not all, dinosaurs were warm blooded. These polar discoveries are strong evidence for warm-bloodedness in at least some dinosaurs.

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