Snakes, lizards, frogs, and the cold-blooded animals that live on every continent except Antarctica.
Limbless hunters that smell with their tongues, swallow prey whole, and number more than 3,000 species worldwide.
The largest living lizard, a 10-foot (3 m) Indonesian predator with serrated teeth and venom glands that let it take down prey as large as deer, pigs, and water buffalo.
