Try to imagine a world without horses. For starters, what would Paul Revere have used to make his midnight ride on, a cow?

Not all dinosaurs were enormous like the 84-foot-long, 30-ton Apatosaurus. TheCompsognathus, for example, approximated an eight-pound chicken. Size up two others.

The most common fossils are bones and teeth, but not all fossils are body parts. Explore the wide-ranging evidence of ancient life that scientists use to understand Earth's prehistoric past.

How many times would your footprint fit into that of a large dinosaur? Could all of your classmate's feet fill up the small crater? Find out with this personalized look at the 35-ton Apatosaur.

Dinosaurs all belong to the same group, but within that group there are many subsets—meat-eating dinosaurs, four-legged dinosaurs, and so on. Try your hand at classification with these eight dinosaur illustrations.

Did you know that squamates have a third eye? Or that the Gila Monster and the Bearded Lizard are the only two known venomous lizards? Discover more interesting facts about squamates.

How does a Veiled Chameleon's body resemble its environment? What colors are a Burmese Python's spots? Use what you know about squamates to bring these drawings to life.

Investigate one of the most successful vertebrates on Earth and find out why some species evolved to be without limbs. Then use what you've learned to create a squamate exhibit.

With unblinking eyes the size of soccer balls and a body that can stretch the length of a bowling alley, the giant squid has long fascinated humans. Investigate the largest invertebrate on Earth.

Travel to the Galápagos Islands and follow in Charles Darwin’s footsteps with this interactive investigation. You’ll have the chance to collect clues as you investigate the islands’ species.