Scaly Surprises

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Darrel Frost has an animal-friendly office at the American Museum of Natural History in New York. In one section of his office, the walls are lined with ten-aria holding lizards and snakes.

Frost walks over to one of the glass enclosures and scoops out a snake with orange banding decorating its body. When this Grey-Banded King snake lifts its head, milky blue eyes come into view. "Its eyes look that way because this snake is getting ready to shed," Frost explains. Like other snakes, this one molts, or sheds its skin periodically, to reveal a newly formed layer beneath. Each of its eyes is covered with a see-through scale that's part of the snake's skin. During the molting process, even the outermost layer of skin covering the eyes will peel off.

This snake is one species within the group of organisms called Squamata (skwah-MAH-tah). "Squamates" is the name for lizards including snakes and limbless lizards. Frost has been interested in squamates since he was a kid. Now, as a curator at the museum, Frost hopes to better educate people about these diverse organisms. That's why he's so excited about the museum's upcoming exhibition that stars lizards.

From projectile tongues to heat-sensing vision, squamates' amazing abilities are bound to wow visitors to the museum. Check out Science World's behind-the-scenes tour to learn more about the animals that Frost is gathering for the exhibition.

What are some characteristics of squamates?
Squamates are vertebrates (organisms with a backbone) that don't have bodily processes for controlling their internal temperature. Instead, these ectotherms keep a healthy body temperature by moving between colder and warmer areas. For instance, a lizard might seek out the cool shade of a tree or the warmth of a sun drenched log. Also, squamates have scaly skin. When these animals molt, they shed the outermost layer of this skin at one time.

How did you become interested in squamates?
I grew up in southern Arizona, where there are many kinds of snakes and other lizards. So I've always been curious about them. All through my teenage years I read everything I could on these creatures. At the time, I never thought studying these amazing animals could become my job. Finally, it did-at a museum.

As a curator at the American Museum of Natural History, what are your days like?
Part of my time is spent looking for new species of lizards and snakes in regions of Africa, Asia, and the Americas. I also oversee the museum's herpetology collections, which include amphibians and reptiles, such as squamates. And I have the opportunity to educate the public about these creatures through exhibitions, like the upcoming show on lizards.

What makes this exhibition so interesting?
The exhibition will highlight the diversity of the world's nearly 8,000 species of squamates. For instance, the smallest squamate - a dwarf gecko - can fit all four of its feet onto a dime. And the largest squamate - an anaconda snake - can grow to a length of more than 10 meters (33 feet).

To show this diversity, the exhibition will include fossils and life-size models of squamates, as well as live animals.

How did you decide which animals to put in the exhibition?
The animals will be on exhibit for several months. So we could exhibit only animals that are hardy in captivity. Among these, I selected a range of different animals-I assembled a variety that would give visitors a sense of how squamates have evolved and become more diverse.

Many of the adaptations that squamates have developed are associated with feeding behaviors. When visitors walk through the exhibition hall, they will notice two distinct feeding behaviors: One group of squamates-called "sight hounds"-hunt by sight. Another group-called "nose hounds"-hunt through other sensory mechanisms.

Would you give an example of a sight hound and a nose hound?
One sight hound, the chameleon, uses its excellent vision to spot prey. Then, like other sight hounds, the chameleon grabs the prey with its tongue. The tip of the chameleon's tongue is extremely pliable and is covered with fluid. So when it projects its tongue-which can extend the length of its body-the tip sticks to its prey. When the chameleon pulls its tongue back in, the prey comes with it.

In contrast, snakes and monitor lizards have hard and deeply forked tongues, which are used to "sniff out" chemicals left by other animals. When you see a snake flicking its tongue out of its mouth, the snake is collecting scent particles from the environment. When the snake brings its tongue back into its mouth, these particles get transferred to two pits called olfactory (related to smell) organs, which are located at the roof of the mouth. These pits can tell whether the scent particles are from prey, an enemy, or other object. Once the snake has zeroed in on its prey, it lunges forward and grabs the prey with its sharp teeth.

What are some other adaptations of squamates?
Squamates use many strategies to avoid being eaten. For instance, most lizards are colored to match their environment. This helps to hide them from hungry predators.

Many other squamates, including several in the exhibition, simply flee as quickly as they can from predators. For example, the Basilisk Lizard is famous for its bipedal (two-footed) flight across water, which is made possible in part by fringes on the hind toes.

The flying gecko has webbed feet and flaps of skin that extend along its body. When this gecko spreads the flaps open like a parachute, it can glide in the air from tree to tree-and escape enemies.

What are some live animals that will be on exhibit?
We will have many live snakes, including vipers and tree boas. Tree boas are interesting because they possess heat-sensing pits in their lips. The pits let the snakes "see" the heat around potential prey. This allows them to more accurately direct strikes, even in the dark.

What part of the exhibition brings out the "kid" in you?
I'm excited to see a lot of really cool-looking squamates gathered in one place. For example, there's going to be a Veiled Chameleon on exhibit. Its bright-green color and the helmetlike ridge on its head will definitely draw a crowd. Visitors will also get to see a 14-kilogram (30-pound) monitor lizard. The exhibition gives me the same sense of wonder as when I was a kid, looking at rattlesnakes in southern Arizona.

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ONLINE ACTIVITY	Uncover Lizards and Snakes Watch and learn about lizards and snakes with expert and curator Dr. Darrel Frost from the American Museum of Natural History. Continue to interactive