Biologists call chameleons the gems of the lizard world. With their often sparkling colors and bizarre bodies, the lizards are popular with photographers -- and collectors.
More than half of the world's 135 kinds of chameleons are believed to live on the island of Madagascar. But collecting for the pet trade and habitat destruction imperils many populations.
Once common, many of the 8 types of Caribbean iguanas are now rare or endangered. Zoos are raising the lizards in captivity in an effort to boost populations and conservationists are trying to restore them to islands where rats and other introduced animals have taken a toll.
The Australian frilled lizard is a kind of dragon lizard that can grow nearly 3 feet long. When threatened, it will erect its dramatic neck frill and open its brightly-colored mouth.
Most challengers retreat from such a hissing monster. But if they don't, the frilled lizard will simply scamper up the nearest tree!
Growing up to 9 feet long and weighing more than 200 pounds, the Komodo Dragon is the world's largest lizard. Found only on a few Indonesian islands, the dragons can live up to 20 years. But they spend much of their time alone, gathering only to breed and feed on carrion.
The lizards also hunt, using their copious toxic saliva to disable prey so they can later move in to feed.
The squat, strong Gila monster is one of the world's two poisonous lizards. Growing up to 2 feet long, the Gila is mainly active at night in its southwestern U.S. home. It tracks its prey by scent, using its poison to paralyze mice and birds.
Whip-tailed lizards come in a dazzling array of shapes and sizes. But most share the ability to shed their slender tails when needed -- leaving a predator holding nothing but a twitching twig of tail! Don't worry, they grow back.
There are about 800 kinds of skinks, but blue-tongued skinks are among the most common. When threatened, this large lizard will puff up, hiss -- and stick out its bright blue tongue, which can be quite startling against its pink mouth.
This flat, toad-shaped lizard is a well-known resident of the dry sandlands of southern North America. Indeed, some mistakenly call them Texas Horney Toads. But its tough skin shows it's no amphibian.
At less than an inch long (snout to tail base), Sphaerodactylus ariasae is believed to be the world's smallest lizard. It was discovered by two biologists in 2001 on Isla Beata, a tiny Caribbean island off the coast of the Dominican Republic. The lizard, which fits easily on a dime, is also believed to be one of the world's smallest vertebrates.
Photo credit: S. Blair Hedges, Penn State University.
The speedy South American basilisk is also known as the Jesus lizard because of its ability to skitter across water. Its toes have special folds of skin that trap air bubbles, allowing it to stay afloat.