Jurassic Giraffes

The sauropods were the tallest, longest, and heaviest animals ever to walk the Earth. Fully grown, some weighed as much as 15 African elephants. Size was their main form of self-defense - they were simply too big to attack. And this was not the only advantage of being a giant. Standing high off the ground, a sauropod could crop leafy twigs out of reach of all other plant-eating dinosaurs. Sauropods were strictly herbivorous. Like leaf-eaters today, they would have had to spend nearly all their time feeding just to stay alive.

Brachiosaurus roamed open countryside where trees mainly grew near swamps and lakes that dried up during the hot summers.

Brachiosaurus roamed open countryside where trees mainly grew near swamps and lakes that dried up during the hot summers.

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Barosaurus

Barosaurus had stocky limbs, a very long neck, and a long, slender tail. Like its better-known relative Diplodocus, it probably had a small skull and peg-shaped teeth for stripping leaves off plants. If it reared up on its hind legs it might have browsed on treetops four storys high. However, experts now suspect it was more of a "hedge cutter" than a high-level feeder.

Barosaurus

Barosaurus used its long tail for balance as it moved.

Like most sauropods, Barosaurus probably could not raise its long neck high, although it could swing the neck sideways as it fed.

The rounded end of this Barosaurus vertebra fitted into a hollow in the next vertebra.__

The rounded end of this Barosaurus vertebra fitted into a hollow in the next vertebra.__

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Impossible necks

Sauropods' necks look impossibly long until you know how they were made. Each neck contained a row of interlocking spinal bones, or vertebrae. These were reinforced below by thin, bony neck-ribs that overlapped each other and stiffened the neck. Above the vertebrae ran muscles, ligaments, and tendons that braced the neck and controlled its movements.

Brachiosaurus

Brachiosaurus resembled an immense giraffe, with nostrils in the bulge ■ above its eyes. Its strong, chisel-shaped teeth could have chopped off woody twigs. Perhaps it browsed among the treetops. However, some scientists think its muscles could not raise the neck very steeply, and, even if they could, its heart would not have been strong enough to pump blood up to the brain.

Trees nibbled by sauropods, would have lost all twigs and leaves up to a certain level. African acacias nibbled by giraffes show just such a browse line.

Inside sauropods

The tough vegetation that sauropods ate had to be ground up to release its nutrients, but sauropods' simple teeth were no good for grinding. Bits of polished stone found in sauropod fossils suggest they had a gizzard - a churning muscular stomach containing a mill of swallowed stones that mashed food to a pulp. I

Many birds and reptiles today, including crocodiles, have a gizzard for this purpose.

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Vertebra

Small intestine

Brachiosaurus y Gizzard

Large intestine

Vertebra muscles

Brachiosaurus cretaceous

248 205 144

Million years ago

248 205 144

Million years ago

Fossil finds

DK GUIDE TO DINOSAURS

CRETACEOUS COWS

The hadrosaurs were the cretaceous equivalent of cows.

They lived toward the end of the Age of Dinosaurs, when they wandered in giant herds through the forests and swamps of North America, constantly munching on ferns, pine needles, leaves, and flowers. Instead of claws, they had hoofed fingertips that allowed them to wade in water or walk on soft ground on all fours. They probably spent most of their lives on open ground, where they could sprint on their hind legs to escape predators such as Tyrannosaurus.

The stiff tail probably could not swing from side to side., corythosaurus

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corythosaurus

Trombone head

The hadrosaur Parasaurolophus had an even stranger crest than Hypacrosaurus. Scientists have come up with all ^ crest kinds of theories to explain its shape, suggesting, for example Parasaurolophus that it might have been a snorkel for breathing underwater looked similar to or an extension of its nose for extra-sensitive smelling. The

Corythosaurus. current theory is that Parasaurolophus could blow through PARASAUROLOPHUS the crest to make honking noises like a trombone.

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