When were the first dinosaurs discovered?

Many people must have noticed old bones in the ground, but they did not attract much attention. In the 1500s dinosaur fossils were thought to be the remains of animals or human giants...

What were killer birds?

After the death of the dinosaurs, and before the development of large mammals, birds were the main predators. Some of these were fearsome, and very similar to some of the dinosaurs...

Giant elephants

There are now only two types of living elephant but in the past there were many different types. Deinotherium was like a giant elephant, 4 m high at the shoulder. It had huge, downward-curving...

Did prehistoric sloths live up trees?

Modern sloths are all slow-moving tree dwellers, but some of their ancestors were very different. Ancient ground sloths grew to an enormous size. They had a massive body, a short tail...

How did whales develop?

Whales evolved from sea lion-like ancestors that returned to the sea. We do not know what the whale's land-dwelling ancestors looked like. Early whales were mostly like huge dolphins...

How did horses evolve?

Animals with hooves carry all their weight on the middle toe of the foot. This was not always the case, however. The evolution of horses shows how they changed from five-toed creatures...

What were sabre-toothed cats?

Sabre-tooth cats survived until as recently as 10,000 years ago, and must have been encountered by prehistoric humans. The best known of these cats was Smilodon, which was more massive...

When did mammals first appear?

A group of mammal-like reptiles preceded the appearance of the dinosaurs. However, these early mammals gradually disappeared during the Triassic Period and were replaced by the true...

When did the dinosaurs die out?

Dinosaurs lived for an enormously long time - some 150 million years - before they died out about 64 million years ago. During their time on the Earth they dominated the land, while...

Are there any living clues to the ancestors of birds?

A South American bird called the hoatzin may have some of the characteristics of the very early birds. The young hoatzin has claws on the front of its wings like the Archaeopteryx,...

Why is there so much argument about the origin of birds?

The difficulty in explaining the evolution of birds is that there are so few fossils. Bird bones are very fragile and honeycombed, with small air spaces. They crumble away very easily...

Which recent discoveries have changed views on the origins of birds?

Many recent discoveries show how birds may have evolved. A fossil found in Madagascar had a sickle-shaped claw on its foot like the predatory theropods Deinonychus and Velociraptor....

Which is the first known bird?

A single fossilized feather was discovered in a German quarry in 1860. It was identical to the feather of a modern bird, and a year later Archaeopteryx was discovered, also in Germany....

What were pterosaurs?

Various reptiles have developed the ability to glide, but the pterosaurs were the only ones to develop true flight. The arms of a pterosaur were quite short, and its entire Wing was...

Are crocodiles dinosaurs?

Crocodiles are not dinosaurs, although they both evolved from the same type of reptilian ancestors at about the same time. Crocodiles have changed very little over The stocky...

Did any ancient reptiles feed on shellfish?

Placodus was a very large, heavily built reptile that probably lived on shellfish. It had spade-like teeth at the front of its mouth for chipping shellfish off rocks. The broad...

What were ichthyosaurs?

Ichthyosaurs are an interesting example of what is known as parallel evolution (when unrelated animals sharing the same habit come to look very similar). In this case, ichthyosaurs...

What were plesiosaurs?

Although dinosaurs did not return to the sea, plenty of other reptiles did. Some of the most familiar are the plesiosaurs, large animals with a barrel-like body and a long snaky neck....

Which giant sauropod dinosaur was well able to defend itself?

Most of the sauropods were too enormous to be successfully attacked by predators. Some of the smaller sauropods developed their own defences. Saltasaurus had body armor, while Shunasaurus...

Which theropod dinosaur was not a meat-eater?

Segnosaurus is an odd dinosaur that scientists have found difficult to classify. It seems to be related to the meat-eating dinosaurs, but it would not have been able to run fast and...

Which dinosaur had a head like a bull?

Carnotaurus, a meat-eating theropod found in Argentina, had a number of puzzling features. It looked rather liked T. rex, but was smaller and had even tinier arms which probably had...

Which dinosaur had a head like a parrot?

Oviraptor was a dinosaur that specialized in eating the eggs of other dinosaurs. It cracked them open with its powerful beak. Oviraptor was only the size of a modern domestic dog...

Which dinosaur had the largest claws?

A claw found in Mongolia from the hand of an unknown dinosaur measured no less than 70 cm in length. As the horny outer part of the claw was missing, it would have been even longer....

Which plant and meat-eating dinosaurs had a crest all the way down their backs?

The plant-eater Ouranosaurus, a close relative of the very common Iguanodon, and many similar large dinosaurs walked mostly on two legs. Ouranosaurus was different because it had a...