Unit Study
Travel back in time to discover the magnificent creatures that once roamed our planet!
Dinosaurs were a group of reptiles that lived on Earth for over 165 million years! The word "dinosaur" means "terrible lizard" in Greek, but don't worry—dinosaurs weren't really lizards. They were their own special group of animals.
These amazing creatures first appeared about 245 million years ago during a time called the Triassic Period. They ruled the Earth until about 66 million years ago, when they suddenly went extinct (disappeared forever).
165+
Million Years on Earth
10,000+
Different Species
245
Million Years Ago
These fierce dinosaurs ate other animals. They had sharp teeth and claws for hunting!
These gentle giants only ate plants. They had flat teeth for grinding leaves and branches!
These dinosaurs ate both plants AND meat. They were very adaptable!
Height: Up to 40 feet (12 meters)
About as tall as a 4-story building!
Weight: Up to 9 tons
Heavier than an elephant!
Lived: 68-66 million years ago
One of the last dinosaurs before extinction
The T-Rex had the strongest bite of any land animal ever! Its teeth could be as long as 12 inches—that's about the length of a ruler!
Height: Up to 10 feet (3 meters)
About as tall as a giraffe!
Weight: Up to 12 tons
Heavier than a T-Rex!
Lived: 68-66 million years ago
Same time as T-Rex!
Triceratops means "three-horned face." Its horns could be up to 3 feet long! Scientists think it used its horns to protect itself from predators like T-Rex.
Height: About 2 feet (0.6 meters)
Only as tall as a turkey!
Weight: About 33 pounds (15 kg)
About as heavy as a large dog!
Lived: 75-71 million years ago
During the Late Cretaceous Period
Velociraptor means "swift seizer." They were actually covered in feathers, kind of like giant birds! The movies made them look much bigger than they really were.
Height: Up to 52 feet (16 meters)
The tallest dinosaur ever!
Weight: Up to 58 tons
As heavy as 12 elephants!
Lived: 154-153 million years ago
During the Jurassic Period
Brachiosaurus had a very long neck—about 30 feet! It could eat leaves from the tops of trees that other dinosaurs couldn't reach. Despite its huge size, it only ate plants!
Bite Force: T-Rex could bite with a force of 12,800 pounds—that's stronger than any land animal alive today!
Brain Size: Some dinosaurs like Troodon were very smart for their time, with relatively large brains compared to their body size.
Feathers: Many raptors and other dinosaurs had feathers! Birds today are actually living dinosaurs.
Heart Power: Some dinosaurs had hearts so powerful they could pump blood up their long necks to their heads!
Baby Dinosaurs: Dinosaur babies looked like mini versions of their parents and may have needed parental care, just like some birds do today!
Speed: The fastest dinosaurs could run up to 40 mph (64 km/h)—about as fast as a car drives through a neighborhood!