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Lizards belong to the order Squamata. Lizard, common name for certain reptiles in the order that also contains snakes, amphisbaenians, and the extinct mosasaurs. Lizards constitute the largest living group of reptiles, with more than 3,000 species in a wide variety of shapes and sizes. |
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| Although lizards may resemble salamanders
and other amphibians, they differ in that lizards have dry scaly skin,
and most have clawed feet and external ear openings. A number of lizards
also have very good eyesight compared with most reptiles. Most lizards
are small with four legs and a long tail that in many species is fragile
and easily broken but will regenerate; the tail of such arboreal (tree-dwelling)
species as the chameleon is adapted for grasping branches. The legs of
some lizards are greatly shortened, or vestigial, making animals such
as the so-called glass snake or slow-worm snake-like in appearance; they
are distinguished from true snakes by their movable eyelids and by differences
in the structure of the skull bones, especially those of the lower jaw.
The bones of the two halves of a lizard's lower jaw are firmly united;
those of a snake are separable. Lizards move in a variety of ways, depending on body structure and habitat. The collared lizard and the basilisk run quickly on well-developed hind legs, and the latter can also run across the surface of water using its greatly developed back legs and whip-like tail. Geckos have special discs on their toes that enable them to cling to smooth surfaces. Some lizards are good swimmers, and a number are adapted for climbing trees. |
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Lizards are found in tropical and subtropical regions throughout the world; few species are found in temperate regions and Arctic areas. Some are burrowing or terrestrial animals; some are arboreal, and others are semi-aquatic. Iguanas are found in all three types of habitats.
Most lizards are harmless and benefit humans by controlling insect populations. Some species are a source of food; some are killed for their skins, although it is now illegal to do so in many countries. A number of species are threatened by encroachment on their habitat, and the largest living lizard, the Komodo dragon, is on the endangered species list. "Lizard," Microsoft(R) Encarta(R) 97 Encyclopedia. (c) 1993-1996 Microsoft Corporation. All rights reserved. P.S. Some of actors on phonecards are not lizards but they look like they are...so they are here:-)) |
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