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 3 to 15 cm (1.2 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.