Reptiles

Leapin’ lizards! It’s Bill Nye’s episode on reptiles.

Reptiles once ruled the Earth – as dinosaurs. Today, there are about 6,500 different species of reptiles. Snakes, lizards, crocodiles, alligators, tortoises, and turtles are all reptiles.

Reptiles are cold-blooded, so most of these animals live where it’s warm. Cold-blooded animals don’t necessarily have cold blood. It just means that the temperature of their blood changes with the temperature where they live. Lizards like to sit around on hot rocks to warm up their blood and speed up their bodies. Alligators let their body temperature be about the same as the water they swim in.

Reptiles are specially adapted to live in different environments. Geckos have developed bristly pads on their toes that let them climb walls to eat insects. Marine lizards on the Galapagos Islands slow their heartbeat down when diving into cold water, to help keep their blood warmer. The beak-shaped jaws of turtles and tortoises make eating plants easy. By adapting, reptiles live in all sorts of places around the world. They’ve been at it for hundreds of millions of years.

See you later, alligator.

The Big Idea

• Reptiles are cold-blooded.
• Reptiles have scaly skin and no hair.
• Reptiles have special ways of living in many different places on Earth.

Did You Know That?

• The biggest reptile in the world is the salt-water crocodile? They grow up to 5 meters (16 feet) long and weigh up to 700 kilograms (1,500 pounds).
• The smallest reptile is the Spaerodactylus parthenopion species of gecko? They are only 1.7 centimeters (0.67 inches) long.
• Some reptiles, like lizards, snakes, and turtles, hibernate in the winter?

Books of Science!

• “Let’s Look at Reptiles” by Harriet E. Huntington. Published by Doubleday and Company, 1973.
• “Reptiles” by Joy Richardson. Published by Franklin Watts, 1993.