Gecko, (suborder Gekkota), any of more than 1,000 species of lizards making up six families of the suborder Gekkota. Geckos are mostly small, usually nocturnal reptiles with a soft skin. They also possess a short stout body, a large head, and typically well-developed limbs. The ends of each limb are often equipped with digits possessing adhesive pads. Most of the species are 1 to 6 inches long, including tail length (about half the total). They have adapted to habitats ranging from deserts to jungles. Some species frequent human habitations, and most feed on insects.
Geckos are spread across six families: Carphodactylidae, Diplodactylidae, Eublepharidae, Gekkonidae, Phyllodactylidae, and Sphaerodactylidae. Of these, the eublepharids—a group that includes the banded geckos (Coleonyx) of the Southwestern U.S., the cat geckos (Aleuroscalabotes) of Indonesiaand the Malay Peninsula, and other areas. These all have movable eyelids.
Most geckos have feet modified for climbing. The pads of their long toes are covered with small plates that are in turn covered with numerous tiny hairlike processes that are forked at the end. These microscopic hooks cling to small surface irregularities, enabling geckos to climb smooth and vertical surfaces and even to run across smooth ceilings. Some geckos also have retractable claws.
Like snakes, most geckos have a clear protective covering over the eyes. The pupils of common nocturnal species are vertical and are often lobed in such a manner that they close to form four pinpoints. A gecko’s tail may be long and tapering, short and blunt, or even globular. The tail serves in many species as a storehouse of fat upon which the animals can draw during unfavorable conditions. The tail may also be extremely fragile and if detached is quickly regenerated in its original shape. Unlike other reptiles, most geckos have a voice, the call differing with the species and ranging from a feeble click or chirp to a shrill cackle or bark.
Geckos are abundant throughout the warm areas of the world, and at least a few species occur on all continents except Antarctica. Geckos’ colors are usually drab, with grays, browns, and dirty whites predominating, though Phelsuma, a genus made up of the day geckos of Madagascar, is bright green and active in the daytime. The banded gecko (Coleonyx variegatus), the most widespread native North America species, grows to 6 inches and is pinkish to yellowish tan with darker bands and splotches. The Tokay Gecko (Gekko gecko), native to Southeast Asia and the Leachianus Gecko of the Island of New Caledonia are the largest species, attaining a length of 10 to 14 inches).