Physiology And Reproduction
The texture and color of a gecko's skin provides excellent camouflage. Four strong legs and five specially-equipped toes on each foot provide for excellent climbing abilities; while two round eyes with vertical pupils allow sharp, nocturnal vision. Diurnal (daytime) geckos, such as the wall gecko (Tarentola mauritanica), of North Africa, Spain, and Croatia, have rounded pupils.
Geckos do not have a forked tongue. Geckos use their tongues to help capture prey and some—like the Australian naked-toed gecko and the Asian tokay gecko—use their tongues to clear their eye scales of dust and debris. The head is relatively large in comparison to the tubular-shaped body, and the long, sheddable tail comprises up to one half of the total body length, snapping off in sections if it is grabbed by a predator. The discarded tail wriggles around on the ground, distracting the attacker's attention and providing precious seconds for the animal to flee. A new tail grows back within a few months. The tail also stores fat, providing nutrients in times of food scarcity. Being cold-blooded creatures, geckos draw their body heat from their environment by basking in direct sunlight or on warm surfaces.
When mating, the male gecko grasps the skin at the back of the female's neck in his jaws and wraps his tail around that of the female, bringing their cloacas—the reproductive openings together. Some species of gecko reproduce asexually, when the female produces fertile eggs without mating with a male. All geckos, except some species found in New Zealand, lay eggs. Some species lay one egg in each clutch while others lay two. Eggs are deposited under rocks, tree bark, and even behind window shutters. Only a few species lay two clutches per year and incubation may take several months. Eggs of the banded gecko and of many other species have a leathery, parchment-like texture, while those of such species as the leaf-toed gecko have a hard, calcareous (containing calcium) shell, the durable nature of which has aided in the wide-spread distribution of many species, particularly the species that reproduce asexually, where just one viable egg can begin a whole new colony.