Category Archives: Dinosaurs and Birds

What Are Dinosaurs?

Dinosaurs survived for an astounding 160 million years (humans, in contrast, have existed for less than one million years). Ranging in size from animals no bigger than pigeons to lumbering giants the size of a truck, they were reptiles, but very different from modern-day reptiles. FACT FILE Key features ■ Lived on land ■ Built… Read More »

Small Ornithischians

The dinosaur family tree is split into two halves: saurischians and ornithischians. The ornithischians were plant-eaters with beaked jaws for plucking leaves and large bellies for digesting them. Though some ornithischians were huge, four-footed giants, many were small, two-footed herbivores that scurried about nervously in forests and scrublands, searching for food and trying to avoid… Read More »

Pachycephalosaurus

This herbivore had a mysterious dome of solid bone at the top of its skull, but what for? One old theory is that males had head-butting contests like rams—but their curved necks might not have been able to take the force. Another theory is that they swung their heavy heads sideways at each other like… Read More »

Ceratopsians

The plant-eating ceratopsians varied from sheep-sized animals to sturdy giants that were bigger than elephants. They grazed in the forests and plains of North America and Asia, perhaps in herds. They had huge, parrotlike beaks that they used to grasp and rip up plants. With their towering horns and huge neck frills, they must have… Read More »

Triceratops

As heavy as a 10-ton truck, Triceratops was built like a huge rhinoceros. It gets its name (“three-horned face”) from the short nose horn and two longer brow horns. Triceratops used its horns and frills like deers use their antlers—to attract mates. BATTLE SCARS Bite marks left by the ferocious Tyrannosaurus on some Triceratops skulls… Read More »

Iguanodontians

The iguanodontians were among the most common and widespread dinosaurs of the Late Jurassic and the Cretaceous. They varied from small, nondescript dinosaurs to giants with horselike faces and hugesails on their backs, but all had beaked mouths for eating plants. The iguanodontian group also includes the large duck-billed dinosaur family. FAMILY FACT FILE Key… Read More »

Dinosaur Droppings

Perhaps the most surprising of all dinosaur fossils are coprolites—fossilized poop. Coprolites have been found all over the world, since they were first recognized for what they were in the 1830s. They can tell us a lot about dinosaurs, most importantly, what they ate. Let’s use it! In the nineteenth century, coprolites were actually mined… Read More »

Hadrosaurids

Also known as “duck-billed” dinosaurs, the hadrosaurids were large plant-eaters with distinctive, ducklike bills that they used to clip leaves from plants. Hadrosaurids may have lived in large herds, and some types seem to have formed nesting colonies in which parents nursed their young after hatching. FAMILY FACT FILE Key features ■ Ducklike bills ■… Read More »

Corythosaurus

Several complete skeletons of Corythosaurus were found in North America, making it one of the best known members of the hadrosaurid family. This crested, duck-billed dinosaur wandered through the swamps and woodlands of the region 75 million years ago, perhaps in herds. Its crest may have been used as a trumpet to keep in touch… Read More »

Scelidosaurus

The most striking thing about Scelidosaurus was its armor. Rows of bony studs and spikes, some as big as a fist, ran from the head to the tail of this plant eater from the Early Jurassic. The armor probably made Scelidosaurus a slow mover and forced it to walk on four legs rather than two,… Read More »