Girdled and Plated Lizards: Cordylidae

views updated

GIRDLED AND PLATED LIZARDS: Cordylidae

CAPE FLAT LIZARD (Platysaurus capensis): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

The plated lizards and the girdled lizards, which have often been separated into their own individual families, are heavy-bodied lizards. The plated lizards have tails that are much longer than the body and are covered with long, rectangular scales. Girdled lizards include the flat lizards, girdle-tailed lizards, and the grass and snake lizards. They have shorter tails that are only about the same length as the rest of the body and are usually covered with spiny scales. The flat lizards have greatly flattened bodies and have few if any spiny scales. The grass and snake lizards have tiny, barely usable limbs that look more like little spines than arms and legs. These lizards slither like snakes.

Many species of plated and girdled lizards are drab-colored and blend into the background. In others, the females and juveniles are dull, but the adult males are brightly and beautifully colored. The girdle-tailed and flat lizards range from 5 to 13 inches (13 to 33 centimeters) in length from head to tail tip; adult grass lizards grow to about 22 inches (56 centimeters) in length, and adult plated lizards reach from 6 to 28 inches (15 to 71 centimeters) in total length.

GEOGRAPHIC RANGE

These lizards live in southern Africa and in Madagascar.

HABITAT

The flat and girdle-tailed lizards, along with many plated lizards, typically make their homes in rocky, dry areas, although some girdle-tailed lizards live in forests where they hide under tree bark or in tunnels. Grass lizards live in grasslands, and plated lizards prefer more shrubby habitats. One species of plated lizard even survives in the sand dunes of a desert, while another lives on the banks of freshwater rivers.

DIET

The species in this family eat almost anything that they can find or catch. The flat and girdle-tailed lizards hunt by ambush, which means that they lie in wait for an insect to wander by. When the insect or other invertebrate (in-VER-teh-breht), which is an animal without a backbone, comes close enough, they rush out to nab it. They will also eat berries and leaves. The plated lizards are not ambush hunters. Instead, they root around through the soil and piles of leaves to find their meals, which are usually invertebrates. Although they can be quite large animals, the plated lizards move very slowly. Nonetheless, they are able to capture small snakes and lizards occasionally for a bigger meal.

BEHAVIOR AND REPRODUCTION

Girdle-tailed lizards, which are all active during the day, are known for the way they defend themselves. When one feels threatened, it scurries into a crack in a rock, blows up its body, and wedges itself in so an attacker cannot reach it. All of the girdle-tailed lizards have very thick scales. When one species, known as the armadillo lizard, is caught too far from a hiding place, it defends itself by rolling into a ball, even grabbing hold of its tail with its teeth, so that the lizard becomes a difficult-to-swallow, scale-covered ball.

LIZARD DEFENSE

Although lizards are very good at running away to a safe hiding place, predators (PREH-duh-ters) or those animals that hunt them for food occasionally are able to capture one. Many lizards defend themselves by losing their tails — purposely dropping them — and later growing a new one. Most lizards can still run very quickly without their tails and dash for cover while the predator snacks on the discarded tail. Snake and grass lizards also drop their tails quickly when they are attacked, but then they have another problem. Because these lizards do not have working arms and legs, and rely on the tail to slither around, they are quite helpless until the new tail grows in.

When flat lizards feel threatened, their body shape allows them to slide into very thin cracks in rocks and out of harm's way. Snake and grass lizards avoid predators with their speed. Although they don't have legs to help them run, they can move very quickly through the grass, sometimes boosting themselves along by pushing off with their long tails. When an attacker grabs the tail, a snake or grass lizard simply drops it and grows a new one.

One of the most unusual behaviors of the plated lizards is that they sunbathe, or bask, in an odd position. They lay on the belly with their arms and legs held up in the air. When frightened, which happens quite often for this shy species, they quickly run for cover under a bush or in some other hiding place or bury themselves in loose soil by moving their arms and legs as if they were swimming. Sometimes they will stay underground for 24 hours before coming above ground again.

Many species of girdled lizards live in groups for much of the year, but during the breeding season, adult males will set up territories and fight to keep other males away. In many species, these battles are little more than showdowns where the males display their bright belly colors. Female girdle-tailed, snake, and grass lizards give birth to baby lizards instead of laying eggs. Each year, the typical female has one to twelve young, which are old enough to have young of their own when they reach two to four years old. The flat lizards, on the other hand, lay two eggs each year in a damp spot within a rock crack. Unlike the girdled lizards, only a few species of plated lizards live in small groups: Most live alone. Also unlike the girdled lizards, the plated lizards are all egg-layers. Scientists still know little about the details on most species of plated lizards.

GIRDLED AND PLATED LIZARDS AND PEOPLE

Many species are easily frightened and are therefore rarely seen up close by humans. The less-shy lizards, especially the groups of colorful flat lizards, however, make for excellent viewing at parks and other spots in southern Africa.

CONSERVATION STATUS

According to the World Conservation Union (IUCN), one species of plated lizard is Extinct, which means that it is no longer in existence. Only two specimens of this lizard, called the Eastwood's long-tailed seps, are known. In addition, five species of plated and girdled lizards are Vulnerable, which means that they face a high risk of extinction in the wild, and five species are Near Threatened, which means that they are likely to qualify for a threatened category in the near future. Many of them live in tiny areas that are now being developed for other uses. A number of the lizards are also very beautiful, which has made them quite desirable for the pet trade.

CAPE FLAT LIZARD (Platysaurus capensis): SPECIES ACCOUNT

Physical characteristics: True to their name, the cape flat lizards are very flat animals. The females and juveniles both have a dark brown back with three wide, whitish stripes that run from head to tail. Their bellies are white with a black blotch in the middle. Adult males are much different. The front half of the upper body is bright blue, sometimes with pale spots or stripes, and the back half, including the tail, is brick-red. On the underside, the throat is light blue; the chest, dark blue, and the belly has a black center blotch. Adults range from about 2.5 to 3.3 inches (6.4 to 8.4 centimeters) from the tip of the snout to the vent, which is a slit-like opening on the underside of the lizard at the beginning of the tail. The tail doubles the overall size, for a total length of about 5 to 6.6 inches (12.8 to 16.8 centimeters).


Geographic range: The cape flat lizard lives in the far southwest portion of Africa, in both South Africa and Namibia.


Habitat: They live in those areas of desert that have many rocks.


Diet: This lizard hunts by ambush, laying in wait in a shady spot under a rock until an insect happens by. At that point, it rushes out to nab the insect for a meal. It also eats flowers and berries when they are available.


Behavior and reproduction: Cape flat lizards are shy animals that run for cover when humans or other potential predators come too close. People usually see them from a distance on top of rocks, especially granite ledges. They may live in small groups. Females lay eggs in November or December and sometimes again a couple of months later. Each time, she lays two large eggs in moist soil beneath or in the crack of a rock.


Cape flat lizards and people: Because they live in deserts away from humans, lizards and humans rarely bother one another.


Conservation status: This species is not listed as endangered or threatened. ∎

FOR MORE INFORMATION

Books

Badger, D. Lizards: A Natural History of Some Uncommon Creatures— Extraordinary Chameleons, Iguanas, Geckos, and More. Stillwater. MN: Voyageur Press, 2002.

Branch, Bill. Field Guide to Snakes and Other Reptiles of Southern Africa. South Africa: Struik Publishers, 1998.

Glaw, Frank, and Miguel Vences. Field Guide to the Amphibians and Reptiles of Madagascar. 2nd ed. Privately printed, 1994.

Mattison, Chris. Lizards of the World. New York, NY: Facts on File, 1989.

Web sites

"Cordylids of the Cederberg." Cape Nature Conservation. http://www.capenature.org.za/cederbergproject/html/cordylids.html (accessed on October 18, 2004).

"Cordylus spp." Melissa Kaplan's Herp Care Collection. http://www.anapsid.org/cordylus.html (accessed on October 18, 2004).

"Plated lizards." Melissa Kaplan's Herp Care Collection. http://www.anapsid.org/plated.html (accessed on October 18, 2004).

"Plated lizards of the Cederberg." Cape Nature Conservation. http://www.capenature.org.za/cederbergproject/html/platedlizards.html (accessed on October 18, 2004).