Types of Dinosaurs

Theropods are the celebrities of the dinosaur world. T. rex, Velociraptor, Spinosaurus, Carnotaurus they're all in this group. What links them is their body plan: two powerful legs, arms that are usually shorter, and feet with three forward-pointing claws. Here's the twist: birds are theropods too. Every chicken, pigeon, and eagle alive today is a living descendant of this group.

Sauropods went in the completely opposite direction. Instead of speed and claws, they went enormous. Brachiosaurus and Diplodocus were so massive that a single one of them weighed as much as a dozen elephants. Their long necks let them reach food that no other animal could get to basically a built-in crane for eating treetops.

Ornithischians are the most varied of all the different types of dinosaurs. Triceratops had three horns and a huge neck frill. Stegosaurus had plates running down its back. Ankylosaurus was basically a living tank with a bone club for a tail. Parasaurolophus had a hollow crest on its head that worked like a musical instrument. All in the same group.

You want records? Sauropods own the size records for all land animals that have ever lived on Earth. Argentinosaurus one of the giant sauropod dinosaurs may have weighed up to 70 tonnes. That's heavier than a dozen African elephants stacked together. Diplodocus had a tail so long it could crack like a whip, producing a sound like a thunderclap.

Among theropods, Spinosaurus takes the crown for sheer size it was longer than T. rex and probably spent a lot of its time hunting in rivers like a giant crocodile. Carnotaurus is the weirdest-looking theropod: it had bull-like horns above its eyes and arms so tiny they were nearly useless.

For ornithischians, Pachycephalosaurus is hard to beat for pure strangeness. The top of its skull was a solid dome of bone up to 25 centimeters thick. Scientists think these dinosaurs rammed each other head-first to compete for mates like bighorn sheep, but a lot more extreme.