The first, the fastest, and the smartest dinosaurs were flesh-eaters. But the very biggest dinosaurs ate nothing but plants.
The first plant-eating dinosaurs appeared on earth several million years after the first flesh-eaters. Like the flesh-eaters, plant-eaters lived during all three periods of the Age of Reptiles.
There were many more kinds of plant-eaters than flesh-eaters. Some made meals out of ferns and bushes. Others were tall enough to eat leaves from the tops of trees. But none of them hunted other animals for food.
Plant-eaters
Many different kinds
Some very tall
Some short
None hunted other animals
Plant-eaters lived during all three periods of the Age of Dinosaurs.
Not all these plant-eaters lived at the same time.
The biggest plant-eaters were the sauropods (SOAR-uh-pods). The sauropods left footprints as big as truck tires. They have names that mean things like “monster lizard” and “titanic lizard.”
For many years, paleontologists thought the biggest dinosaur of all time was a sauropod called Brachiosaurus (BRACK-ee-uh-SOAR-us).
Brachiosaurus was as long as three school buses. But now, fossil hunters have found bones of three dinosaurs that were even bigger:
We don’t know much about these giant sauropods because only a few of their bones have ever been found. But some paleontologists think Seismosaurus might have been over 150 feet long—as long as six school buses!
Was Seismosaurus the biggest dinosaur of all? No one knows. Dinosaur hunters discover new fossils every year. It’s possible that any day they’ll dig up the bones of an even bigger giant.
Turn the page to see some of our favorite plant-eaters!
Stegosaurus
(STEG-uh-SOAR-us)
This name means “roofed lizard.”
Stegosaurus was about the size of a mini-van. It had four long spikes on the end of its tail. It had big, flat plates growing out of its back.
Stegosaurus had a very small head. For many years, most books described Stegosaurus as having a brain the size of a golf ball. But paleontologists now think that Stegosaurus’s brain looked more like a hot dog!
Stegosaurus brain
Hot dog
(an-KYE-luh-SOAR-us)
This name means “fused lizard.”
Ankylosaurus was the size of an army tank—and built like one! Its body and head were covered with armor. The armor was made of bone. It protected Ankylosaurus from flesh-eating dino-saurs like T. rex.
Ankylosaurus had a big club on the end of its tail. Paleontologists think Anky-losaurus used its tail club to smash the feet and legs of any dinosaur that tried to attack it.
(ED-mont-uh-SOAR-us)
This name means “lizard from Edmonton.”
Edmontosaurus also used to be called Anatosaurus (uh-NAT-uh-SOAR-us).
Edmontosaurus had a bill like a duck’s. It also had over a thousand teeth! When any of its teeth wore out, new ones grew to replace them.
Paleontologists believe that Edmontosaurus took good care of their babies. They protected their nests. They gathered food for the babies to eat. They probably looked after their babies until they were old enough to look after themselves.
(try-SEHR-uh-tops)
This name means “three-horned face.”
Triceratops had a face like a scary Halloween mask. It had a beak like a parrot’s. It had three long horns.
Paleontologists say that Triceratops used their horns mostly to fight off other dinosaurs that were trying to eat them. But they also think that sometimes two male Triceratops would lock horns and fight with each other over a female.
(dih-PLOD-oh-kus)
This name means “double beam” (because of the shape of the bones in its tail).
Diplodocus was a long, skinny sauropod. It had a long tail and very strong legs. Some paleontologists think Diplodocus could balance on its back legs and its tail, then stretch up to eat from the very tops of trees.
Diplodocus ate almost all the time! Its mouth was so small compared with its body that it had to take hundreds of bites to make a meal.
(BRACK-ee-uh-SOAR-us)
This name means “arm lizard” (named for its long front legs).
Brachiosaurus looked a little bit like a giraffe. It had a very long neck and a small head. It had front legs that were longer than its back legs. But Brachiosaurus was twice as tall as a giraffe. And its nostrils were on the top of its head!
