Apatosaurus: The giant long-necked plant-eater of the Jurassic

Apatosaurus is one of the most spectacular animals in the museum's land gallery. It carries a vast body on four pillar-like legs, with a neck and tail that are astonishingly long. It was a sauropod — a member of the diplodocids — and lived during the Late Jurassic. Despite the name, it is a very well-known "old friend" among dinosaurs.

Its body

Apatosaurus was enormous, reaching more than twenty metres long. Its neck was built from strings of vertebrae and stretched up to reach high leaves; its tail was just as long and powerful, like a long whip. Four legs stood as thick, straight pillars beneath its weight. The head was tiny compared with the body, and the teeth were small and suited to cropping plants, not chewing them.

How such a long neck was held up has long been debated. It may have been raised by a "suspension bridge" of ligaments, or the animal may often have kept its head low, balancing its body with the long tail.

Where it lived and what it ate

Apatosaurus was a plant-eater that ate leaves from high up or low plants. A body that large needs a huge amount of food every day, so it probably spent much of its time walking and eating. It lived in the Late Jurassic, when western North America held broad, damp plains full of the conifers and ferns it fed on.

Where its fossils were found

Most Apatosaurus fossils come from western North America, especially the Morrison Formation in the United States. That layer holds a wealth of Late Jurassic dinosaurs and is one of the most important windows we have into that time.

What the fossils tell us — and what they do not

Fossils preserve the skeleton, the size and the pillar-like legs, but the skin colour, the colour of the tail tip, how the neck was normally held and what call it made are rarely preserved. So the colours and pose you see are evidence-informed reconstructions.

A note for grown-ups

You could help a child picture the scale: "If we stretched Apatosaurus out on the playground, how long would it be?" Starting from size, then wondering how much food such an animal needs each day, is a natural and fun lesson.