Iguanas are those lizards that belong to the Iguanidae family. There are about seven hundred species of them. They are found only in the New World, in certain islands in the South Pacific, and in Madagascar. In eastern United States the most common iguana is the fence lizard. It is greyish brown but has blue scales underneath its body. It was given its name because it is often seen running along fences or resting in the sun on them.
Western iguanas include the horned lizards, the sand lizards, and the utas. The horned lizards, or homed toads as they are sometimes called, may, if frightened, squirt a small amount of blood from their eyes. The utas are among the smallest iguanas, the adults measuring only about five inches in total length. Another interesting iguana of the Southwest is the chuckwalla. If an enemy threatens it, it hides in between rocks and inflates its body. The enemy finds that it is almost impossible to pull the inflated chuckwalla out of its hiding place.
The anoles are a fascinating group of iguanas. They are found in tropical or subtropical regions. Depending on the temperature and light, they can change their colour from brown to green. The males have a red skin flap on their throats which they inflate during courtship or as a warning to other males to keep out of their territory. The largest iguanas are the common iguanas which live in tropical Central and South America. They may be as long as six feet including their tails, but the tails account for about two-thirds of the total length. They look like animals which have survived from the earliest days of the earth.
Common iguanas are vegetarians; they eat leaves and fruit. With their strong claws they can easily climb to the highest limbs of the tropical forest trees. The females lay their eggs in the ground; the young iguanas hatch in about two months. People who live in the regions where the common iguanas are found consider them to be a great food delicacy. The iguanas, however, are not easy to capture since they can escape by climbing, by running, or even by swimming. Two of the rarest iguanas live in the Galapagos Islands off the coast of South America. The first of these is the marine iguana, the only iguana which feeds on seaweed. One of their favourite foods is sea lettuce. They are excellent swimmers, but usually feed close to shore at low tide. After they eat, they spend the rest of the day basking in the sun along the rocky coast.
Most of the marine iguanas are blackish like the volcanic rock on which they live. However, on some of the islands the iguanas have patches of red or green during the mating season. At this time too, there are apt to be head-butting battles between males and even between females looking for places in the sand where they could lay their eggs. Each female lays only two eggs—some other species of iguanas may lay as many as eighty eggs—which hatch in about two and a half months. Newly-hatched marine iguanas are about ten or eleven inches long; adults may be from three to four feet in length.
The other Galapagos iguanas are the land iguanas which are from two to four feet long. They Jive on cacti and other plants. Their numbers have been greatly reduced by dogs, by pigs which eat iguana eggs, and by humans who use them for food.
There are two species of land iguanas found on different islands of the Galapagos. In one species the males become red and yellow during certain seasons; in the other species there is no colour change from the usual yellowish-brown. In 1964, leading scientists of many countries established the Darwin Research Station in the Galapagos. One of the purposes of this biological station is to find out, by studying various plant and animal interrelations, what conservation measures are necessary to save the rare and unique animals of these islands, including the land iguanas.
There are now thriving colonies of these only on two of the eight islands.Both the marine and the land iguanas of the Galapagos were first described by Charles Darwin in his Journal. He visited the Galapagos early in the nineteenth century, on a trip around the world.
Iguanas Pictures
