iguana [key], name for several large lizards of the family Iguanidae, found in tropical America and the Galapagos. The common iguana (Iguana iguana) is a tree-living, strictly vegetarian species found along streams from Mexico to N South America. Members of this species are 3 to 6 ft (90–180 cm) long, with the tail accounting for two-thirds of the length. They are bright green with dark stripes on the tail. A crest of spines runs from the neck to the tail. The flesh and eggs of the common iguana are valued as food. Spiny, or black, iguanas (species of Ctenosaura) are ground-living vegetarian lizards found from Baja California to Central America. The chuckwalla (Sauromalus obesus) and the desert iguana (Dipsosaurus dorsalis) are desert species of the SW United States and NW Mexico. The 16-in. long (40-cm), greenish chuckwalla is the largest U.S. lizard except for the gila monster and is known for its ability to inflate itself, making it difficult to extract from crevices. The gray-brown desert iguana is marked with dark spots and stripes; it lives in burrows made by other animals. Both feed on cactus flowers and fruits and tender desert plants. Basilisks Basiliscus (species), found along streams in tropical America, are large iguanas that can walk in an upright position; males are crested. A marine iguana (Amblyrhynchus cristatus), the only marine lizard, is found in the Galapagos Islands, where there is also a land species (Conolophus subcristatus). The large, diverse iguana family includes many smaller species not called iguanas. They are found throughout the temperate and tropical Americas, as well as in the Fiji Islands and on Madagascar. Most North American lizards belong to this family, including the collared lizards, the utas, the swifts, the so-called horned toads, or horned lizards, and the American chameleon, or anole (not a true chameleon). Most members of the family feed on insects and other small animals as well as some plant matter. In nearly all species the females lay eggs in the ground. Iguanas are classified in the phylum Chordata, subphylum Vertebrata, class Reptilia, order Squamata, family Iguanidae.
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