Think About This!
The earliest squamates lived about 200 million years ago, the same time that dinosaurs were starting to flourish. These early squamates shared similar characteristics. Over time, squamates evolved many different characteristics and ways of life. For example, some squamates lost their legs; one of these legless groups is called snakes.
Green Iguana
You’ll find most Green Iguanas lounging in tropical vegetation along streams. That’s where they’ll find a typical meal of leaves and fruit. They also eat insects, which they catch with their short, thick tongues.
Green iguanas have strong digits and claws for moving in trees or over rocks, and long legs for stretching from branch to branch.
Rhinoceros Iguana
Rhinoceros Iguanas are found on a few Caribbean islands where they live mostly on cactus fruits, flowers, and other plants. They have short legs and spend their time on the ground. Rhinoceros Iguanas evolved in the West Indies with few natural predators. But introduced dogs, cats, and rats have made most modern species rare and endangered.
Frilled Lizard
Without warning, a predator approaches an unsuspecting Frilled Lizard. It’s too late to run, but the lizard still has a chance. Suddenly, it opens its mouth and hisses loudly. At the same instant, a colorful spiked fan of skin opens like an umbrella around the lizard’s head. This “frill” makes the lizard look much larger and more intimidating. The unexpected response startles the predator and gives the Frilled Lizard time to escape.
Frilled Lizard
This amazing ability gives the Frilled Lizard its name, but it’s not the lizard’s only defense. Even though the frill is brightly colored, the lizard’s pointy scales are usually green or brown to blend in with the forest background. On the ground, it sprints on its hind legs. Its long tail helps it balance while on two legs. The Frilled Lizard also has strong claws to help it climb through trees and over rocky surfaces. Frilled Lizards are prey to larger reptiles including other lizards and snakes, birds of prey like ospreys and owls, and a few mammals like dingoes and feral cats.
Frilled Lizard
Frilled Lizards spend lots of time in trees, but they’ll climb down to look for dinner. It’s the only squamate that routinely runs on its hind legs to capture prey. They catch mostly insects and spiders with their short, thick tongues.
Veiled Chameleon
It’s hard to spot a chameleon as it sits motionless among the leaves. Its long tail curls around the slender branch as it holds itself steady. The lizard keeps one eye focused on a predator on the ground, while the other follows an insect buzzing nearby. In a flash, the chameleon’s tongue shoots out, stretching longer than its body. The tongue’s sticky tip snaps up the insect and the lizard whips it back into its mouth. The hunt is over in less than a second.
Veiled Chameleon
Its tongue may be lightning fast, but the chameleon itself is a slow mover. The chameleon walks from branch to branch with its thin legs and mitten-like feet, which have a strong opposable grip like human hands. It can wrap its long curled tail around branches for extra support.
Veiled Chameleon
Chameleons are stealthy insect-eating predators. But they’re often prey too. Raptors, owls, monkeys, and snakes all eat chameleons. One of the most amazing ways they avoid predators is their remarkable capacity for color change, which helps them blend in with their surroundings. They do this using a complex system involving hormones, nerves, and specialized pigment cells in their skin. They take advantage of their ability to camouflage by staying completely still to avoid being noticed. They also use color change to communicate with each other.
Crested Giant Gecko
Ever seen a lizard walk upside down on the ceiling, or up a glass window? For people living in the tropics, this isn’t such an unusual sight. They often see these lizards called geckos come out at night. The secret to the gecko’s amazing climbing ability is in their toes.
Crested Giant Gecko
Like other geckos, they have specialized toe pads covered with millions of microscopic hair-like projections. These “hairs” create a remarkably strong attractive force that allows the entire weight of the gecko to be supported by just one toe.
Crested Giant Gecko
Climbing is one way that geckos avoid predators. Like many squamates, their scales have colors or patterns to help them blend into the background. Geckos are also hard to spot because they’re nocturnal, or active at night. They can do something few squamates can do — they make chirping or clicking sounds. Like many squamates, if a gecko is caught it can distract a potential predator by constricting its muscles to break off its tail. The tail twitches on the ground for a few minutes, giving its previous owner a chance to escape. Eventually, a new tail can regenerate in its place.
Crested Giant Gecko
When geckos are the hunters, they usually catch insects and spiders with their teeth. Crested Giant Geckos also eat fruit. These night creatures have big eyes with large, vertical pupils that open wide to capture available light.
Water Monitor
Monitors are meat-eating squamates that hunt birds, other reptiles, mammals, fish, and even eggs. Like snakes and many other squamates, they can track prey by flicking their long, forked tongues to pick up molecular clues in their environment. This helps the monitor identify the prey and follow its trail. Monitors capture prey with powerful jaws and sharp teeth — and can even swallow their victims whole.
Komodo Dragon
Imagine a 10-foot long lizard with sharp teeth and a long, powerful tail that attacks wild pigs and deer with mighty jaws. This ferocious creature is real. It’s the Komodo Dragon, the world’s largest living lizard. Komodo Dragons belong to a group of lizards called monitors. Not all living monitors are as huge and forceful as the Komodo Dragon, but they do share some common features. Monitors have strong legs and long, muscular tails. Despite their stocky bodies, they’re surprisingly fast runners and most monitors are also good swimmers.
Komodo Dragon
The largest monitor lizard, the Komodo Dragon, generally has no predators — except other Komodo Dragons. They might lash out with their strong claws and sharp teeth, or use their powerful tail as a weapon. Sometimes they inflate their bodies and hiss to intimidate an attacker. They might also stand on their hind legs to look more threatening. Most of the time, monitors simply rely on their impressive speed to escape a predator.
Emerald Tree Boa
A long, slender tree boa drapes over a branch in a dark, tropical forest. Even in the pitch black, the Emerald Tree Boa knows when its prey is nearby. Like other squamates, it can track its prey with the help of its long, forked tongue. The snake also has pits along its lips that allow it to "see" the heat given off by prey.
Emerald Tree Boa
The tree boa slowly hangs down above a rat. The snake has long teeth that point backwards into the mouth and are helpful in holding onto prey. It’s a constrictor, which means it will squeeze its prey to death. In a flash, the boa wraps its body around the rat. Each time the rat exhales, the snake tightens it grip until the rat can breathe no more. The snake eats its victim whole. Like all snakes, it has an extremely flexible skull and elastic ligaments in the lower jaw.
Emerald Tree Boa
After its meal, the tree boa glides away. Like all snakes, its movement depends on a series of strong muscles attached to its many ribs. It uses its belly scales to anchor one part of the body on a surface while it pushes another part of its body forward.
Tree boas are effective predators, but they’re also prey. The same heat-sensing pits and long tongues that help them track prey also help them detect predators. Their bright green color allows them to blend in with the surrounding vegetation.
Red Spitting Cobra
Suddenly, a slender, dark red snake rises out of the grass to confront a leopard. Its neck is flattened and spread out in a “hood” that makes it look big and impressive. The snake bares its fangs and sprays a stream of venom into the leopard’s eyes. The poison blinds the leopard for a moment and the snake slithers away. The leopard may be much larger and faster than the snake, but it can’t compete with the venomous “spit” of the Red Spitting Cobra.
Red Spitting Cobra
This snake has short, hollow fangs in the front of its mouth. Each fang has a narrow opening that releases the venom under great pressure. A spitting cobra can shoot venom up to several feet away with amazing accuracy. It’s a powerful weapon, but the spitting cobra only “spits” to defend itself. When it attacks prey, it bites the victim and injects venom into its flesh.
Red Spitting Cobras live on the ground. They hunt ectothermic animals like frogs. Like other snakes, they track their prey by picking up scents with their long forked tongues, and they can eat prey larger than their heads. Their elastic jaws can stretch wide open and swallow an animal whole.