Angleheads, Calotes, Dragon Lizards, and Relatives: Agamidae

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ANGLEHEADS, CALOTES, DRAGON LIZARDS, AND RELATIVES: Agamidae

SPINY AGAMA (Agama hispida): SPECIES ACCOUNTS
FRILLED LIZARD (Chlamydosaurus kingii):SPECIES ACCOUNTS
FLYING LIZARD (Draco volans):SPECIES ACCOUNTS

PHYSICAL DESCRIPTION

Agamids can be rather plain, or they can look quite strange and unusual. Their bodies may have crests, or ridges of large spines, on the back and tail. They may have neck frills and folds and body decorations, such as lumps and spines on the head. Some agamids have dewlaps, or throat fans.

Agamids come in many colors. Some are gray, brown, or black, but they may also have more showy colors. The Thai water dragon is bright green with golden eyes. The rainbow lizard is yellow or orange on top and blue on the bottom. Some species, or types, can change color rapidly, depending on their mood. Their lengths range from 10 inches (25.4 centimeters) to 36 inches (91.4 centimeters). In many species, males look different from females. They often have brighter colors, especially during the mating season, and bigger body parts, such as heads. All agamids have four well-developed limbs, or legs. There are usually five toes on each foot.

The head of an agamid is large and triangular, with a visible neck area. They all have movable eyelids and a circular pupil. In most agamids the ear opening is on the side of the head. Body scales are rough or spiny in most species. Some agaminds have a small or large crest, like a fin of scales, along their backs. Unlike some other lizards, agamids never lose their long tails when chased by a predator (PREH-duh-ter), or an animal that hunts the agamid for food.

GEOGRAPHIC RANGE

Agamids are found in Europe and Africa and throughout Southeast Asia, including Indonesia and the Philippines. They also inhabit New Guinea, the Solomon Islands, and Australia.

HABITAT

Agamids prefer to live in sandy and rocky deserts. They also may be found in dry forest habitats and dry scrub areas, which are flat areas with small bushes. Flying lizards are found in rainforests, areas with a great deal of rain and warm temperatures throughout the year. The Asian water dragon lives part of the time in trees near streams.

DIET

An agamid does not chase insects for food. Instead, it sits and waits in hiding until an insect comes by. Then out darts its sticky tongue to capture the insect and eat it. A few agamids, such as the Dabb spiny-tailed lizard, prefer plants for food.

BEHAVIOR AND REPRODUCTION

Agamids are diurnal (die-UR-nuhl), or active during the day. They spend a lot of time basking, or resting, in the sun. Some species prefer to sun themselves on flat rocky areas, while others like to climb onto tree trunks or shrubs to sunbathe. If the desert species get too hot, they go into cooler underground burrows, or holes, to rest.

Agamids have different ways of protecting themselves against predators. The bearded dragon lizard, for example, has spiny body scales. Some agamids run underground or into a rock crevice (KREH-vuhs), or crack. The Dabb spiny-tailed lizard runs into its burrow and lets the spiny part of its long, thick tail hang out. If the predator keeps pestering it, the lizard swishes its tail from side to side, which discourages most predators.

THE WEIRDEST LIZARD?

The thorny devil lizard of the Australian desert certainly looks strange. It has horns, knobs, warts, and pointed armored scales all over its 8-inch-long (20.3-centimeter-long) body. But it is a gentle creature that feeds only on ants. This lizard can eat up to five thousand black ants at a single meal! It laps the ants up with its sticky tongue. This lizard changes its color to match its surroundings, and it also can change its color pattern and body size. When bothered, the thorny devil can take in air so that it puffs up to a larger size. Thorny devils drink by collecting dew on their skin. Dew is made up of little drops of water that gather on cool surfaces. The lizard's assorted skin bumps are arranged so that dew flows through them toward the corners of the mouth.

Agamid males typically are very territorial, meaning that they are protective of their living areas. A male agamid mates with females inside his territory, where several females may live. When challenging other males for a mate, an agamid may bob its head, push up on rocks to make it look bigger, open and close its mouth, and enlarge its dewlap, the expandable flap under the chin. Some males become brightly colored during courtship. The Indian bloodsucker agamid expands the dewlap during courtship, and its head and throat turn bright red. That color gives the "bloodsucker" its name.

Most agamid females lay soft-shelled eggs after mating. The smaller agamid species lay a small number of eggs. The larger species may lay up to two dozen eggs. There may be one egg clutch, or group, per season or several throughout the year. Eggs are usually buried in damp soil or in leaf litter. There are some agamid species, such as the toad-headed lizards, that give birth to live young.

AGAMIDS AND PEOPLE

Agamids do not normally interact with people. They eat many insects, and so they are considered useful animals. A few species are captured for the legal and illegal pet trade, and some larger species are exhibited in zoos. A few larger species are caught for food.

CONSERVATION STATUS

Most agamids are not threatened. The World Conservation Union (IUCN) labels two species as Endangered, meaning that they face a very high risk of extinction in the wild. One species is listed as Near Threatened, meaning that it might soon face serious threats. Habitat loss, or loss of their preferred living area, is a major problem for agamids. The introduction of new predators, such as cats and rats, to their living areas has also harmed them.

SPINY AGAMA (Agama hispida): SPECIES ACCOUNTS

Physical characteristics: Spiny agamas are medium-size lizards, about 12 inches (30.5 centimeters) long. They are usually gray-brown or bright green, but these colors can change. During the mating season, males have a blue head with a red throat and yellow shoulders. Females are plainer, with orange, brown, and cream-colored blotches. Spiny agamas have spines along their backs and two fanglike teeth in the front of their mouths. These teeth are strong enough to pierce tough insect shells and can give a painful bite.

Geographic range: The spiny agama lives in southern Africa.

Habitat: Spiny agamas live in and between sand dunes, or hills of sand piled up by the wind, in coastal areas and in dry semidesert areas, where some water is available.

Diet: Spiny agamas eat ants, beetles, and termites.

Behavior and reproduction: Spiny agamas live alone. They usually stay close to the ground, digging short tunnels at the base of bushes. They also climb small upright items, such as fence posts. Spiny agamas are sit-and-wait predators, meaning that they do not chase after their insect food. They wait until the insect wanders by and then catch and eat it.

During the mating season, spiny agama males become quite colorful. Males fight to defend their living and mating territories. They will mate with several females within this area. Each female will lay about forty-five groups of eggs, each containing about thirteen eggs.

Spiny agamas and people: Spiny agamas do not interact with people. There is a popular belief that these lizards climb trees to look skyward to see if it will rain.

Conservation status: The spiny agama is not threatened. ∎

FRILLED LIZARD (Chlamydosaurus kingii):SPECIES ACCOUNTS

Physical characteristics: The frilled lizard is large, with gray-brown coloring. Its length ranges from 2 to 3 feet (61 to 91.4 centimeters). Adult males weigh about 30 ounces (850 grams) and females about 14 ounces (397 grams). A frilled lizard has long legs and a medium-long tail. It has a large neck frill, or neck folds, made of thin skin. Most of the time, the frill is kept folded like a cape over the lizard's shoulders and back. The tongue and mouth lining are pink or yellow.

Geographic range: Frilled lizards are found in northern Australia and southern New Guinea.

Habitat: Frilled lizards inhabit grassy woodlands and dry forests. These tree-living lizards are seldom found very far away from trees.

Diet: Frilled lizards eat cicadas (suh-KAY-duhs), ants, spiders, and small lizards.

Behavior and reproduction: The frilled lizard spends most of its time on tree trunks and low branches. It is active during the day and comes down to the ground after it rains and to search for food. When it is threatened or alarmed, the frilled lizard quickly enlarges the big, reddish-orange, fanlike frill around its neck. This frill can enlarge to a size of 8 to 12 inches across (20.3 to 30.5 centimeters). The frill has zigzag edges and red, blue, and brown spots. At rest, the folded frill helps keep the lizard cool. It also acts as camouflage (KA-mah-flahzh), a sort of disguise, allowing the lizard to look like a branch or bark.

If a predator threatens, at first the frilled lizard may hide, become absolutely still, or run to the nearest tree. If cornered, the frilled lizard faces the predator. It enlarges its frill and opens it brightly colored mouth. Sometimes it hisses, stands up on its hind legs, or leaps at the predator. If these actions do not work, frilled lizards can run on their hind legs for short distances.

Frilled lizards mate during the wet season. Males are territorial, protecting their living area. They may use their frills to attract mates. Females lay a clutch or group of eight to fourteen eggs twice a year, in spring and summer. Nests are made in flat, sandy soil, surrounded by thin grass and leaf litter. They are not covered.

Frilled lizards and people: Frilled lizards are the reptile emblem of Australia. They are shown on the Australian two-cent coin. There are books for children about frilled lizards, and a frilled lizard was featured on one automobile commercial on television. Fire-prevention road signs in Australia say, "We like our lizards frilled, not grilled." The frilled lizard is protected by law in Australia.

Conservation status: The frilled lizard is not threatened, but problems are expected. Toxic, or poisonous, cane toads have been introduced to the areas in which they live. Thought to be helpful, these toads instead have become pests, eating lizards and other small animals. In some areas, land clearing and the introduction of cats have caused frilled lizard numbers to decline. ∎

FLYING LIZARD (Draco volans):SPECIES ACCOUNTS

Physical characteristics: The flying lizard is a slender, long-legged, small lizard. It measures 8 inches (20.3 centimeters) from head to tail tip. It has winglike body parts formed from thin skin stretched over extra-long ribs. When the lizard leaps from a tree, these body parts are stretched out at right angles to the body, forming a pair of gliding wings. At rest, these skin "sails" are folded along the body, keeping the lizard's appearance slim. The lizard's body color is gray or brown, but the wings are brightly colored. Male and female wing colors differ.

Geographic range: The flying lizard lives in Indonesia, Thailand, Malaysia, and the Philippines.

Biomes: Coniferous forest, deciduous forest, rainforest

Habitat: Flying lizards live in open forests and rainforests.

Diet: Flying lizards eat ants and other insects.

Behavior and reproduction: These small lizards live in trees. On land they are clumsy and easy victims for predators. When scared, they run up a tree. When threatened, they leap off the tree. With their "wings" stretched out, these long-tailed, lightly built agamid lizards glide gracefully. The wings act like parachutes. When gliding, these delicate, slender lizards use their tails to steer and sometimes can travel as far as 55 yards (50.3 meters). They gently land on another tree, head up. When they land, they run up the tree, getting ready for their next flight.

During mating season, male flying lizards defend their territories. They court females by displaying their bright yellow throat flap. Females lay one to four eggs.

Flying lizards and people: Flying lizards do not interact with people.

Conservation status: Flying lizards are not threatened. ∎