Reptiles
How would you like to walk up walls and across ceilings? Geckos can do exactly that! These incredible lizards have special feet that stick to almost any surface-even smooth glass! Geckos are found in warm places all around the world, from tropical rainforests to desert rocks to the walls of your house. Some geckos can change color. Others have no eyelids and lick their eyeballs clean with their tongues! With over 1,500 species, geckos are one of the most diverse groups of lizards on Earth. Let's climb into the amazing world of geckos!
Geckos come in an amazing variety of colors and patterns! Leopard geckos have spotted yellow and brown skin that looks like a tiny leopard. Crested geckos have a fringe of skin running from their eyes down their backs like a little crown. Day geckos are bright green with red spots. Leaf-tailed geckos from Madagascar look exactly like dead leaves-bark texture, bite marks, and all! Geckos can be green, brown, yellow, orange, blue, or even bright pink!
Most geckos have big eyes with vertical slit pupils, like tiny cat eyes! Their eyes are covered by a clear, fixed scale instead of movable eyelids-so geckos cannot blink! To keep their eyes clean and moist, most geckos lick their eyeballs with their long tongues. Watching a gecko clean its own eyeball is one of the funniest things in the reptile world! Some geckos have round pupils and are active during the day, but most are nocturnal with slit pupils for night vision!
Gecko toes are their most famous feature! Most geckos have special toe pads covered in millions of microscopic hairs called setae. Each hair splits into hundreds of even tinier tips called spatulae. These tiny structures create a force called van der Waals attraction that lets geckos stick to almost any surface-glass, metal, wood, even Teflon! A single gecko foot can support the weight of the entire gecko hanging from a smooth ceiling!
Geckos live in warm regions all around the world! They are found in deserts, rainforests, mountains, and on islands across the tropics. Some species have followed humans around the world and now live in houses, hotels, and buildings in warm climates. The common house gecko is found on every warm continent! Geckos need warmth because they are cold-blooded-their body temperature depends on their surroundings!
Different geckos prefer different habitats! Leopard geckos live in the rocky deserts of Afghanistan and Pakistan. Tokay geckos climb the walls and trees of Southeast Asian rainforests. Day geckos bask on sunny branches in Madagascar. Leaf-tailed geckos blend into the bark of rainforest trees. Some geckos live in sand dunes, others in rocky crevices, and some even live high in the mountains. Wherever it is warm, there are probably geckos!
Many geckos are amazing at hiding! Leaf-tailed geckos press their flat bodies against tree bark and become almost invisible. Mossy geckos from Vietnam look like clumps of moss growing on rocks. Some desert geckos burrow into sand during the hot day and come out at night. Flying geckos have flaps of skin along their sides that flatten against tree trunks, eliminating any shadow that might give them away!
Most geckos eat insects and spiders! They hunt at night, using their amazing eyesight to spot prey in near-total darkness. Gecko night vision is 350 times more sensitive than human color vision! They eat crickets, moths, beetles, cockroaches, mosquitoes, and flies. A house gecko can eat hundreds of mosquitoes and cockroaches every month, making them welcome guests in many tropical homes around the world!
Larger geckos eat larger prey! Tokay geckos-one of the biggest gecko species at 14 inches-eat mice, small birds, and even other smaller geckos. New Caledonian giant geckos munch on fruit and nectar in addition to insects. Some gecko species are entirely fruit-eating. Day geckos love to lick nectar from tropical flowers. Crested geckos eat a mix of fruit, nectar, and small insects in the wild!
Geckos have interesting hunting styles! Most geckos are sit-and-wait predators-they stay perfectly still until an insect walks close enough to grab. Then they strike with lightning speed! Some geckos actively stalk their prey, moving slowly and then pouncing. Geckos grab insects with their mouths and swallow them whole. They have tiny teeth for gripping but cannot chew, so their food must be small enough to swallow in one gulp!
Most geckos lay eggs! Females typically lay two eggs at a time in a protected spot-under bark, in rock crevices, or buried in moist soil. Gecko eggs have soft, leathery shells that harden after being laid. Some species, like house geckos, lay eggs with hard shells that they stick to walls! A few gecko species give birth to live babies instead of laying eggs. Leopard geckos lay 2 eggs every 2 to 3 weeks during breeding season!
Temperature determines whether gecko babies are male or female! In many gecko species, the temperature of the eggs during development decides the baby's sex. Warmer temperatures might produce more males, while cooler temperatures produce more females (or the opposite, depending on the species). This temperature-dependent sex determination is common in reptiles but is especially well-studied in leopard geckos!
Baby geckos are tiny but ready to go! Hatchlings are miniature copies of their parents, complete with working sticky toe pads. A newborn leopard gecko is about 3 inches long. Baby geckos can hunt small insects within their first day or two of life. They shed their skin frequently as they grow-some baby geckos eat their shed skin for the nutrients! Young geckos grow quickly, often reaching adult size within their first year!
Gecko mothers do not care for their babies! Once the eggs are laid, the mother leaves and the babies are on their own when they hatch. Baby geckos must find food and avoid predators by themselves from day one. Their small size makes them targets for birds, snakes, spiders, and even larger geckos. Many baby geckos stay hidden during the day and hunt only at night when they are safer from predators!
Geckos are nature's pest controllers! A single house gecko can eat hundreds of mosquitoes, cockroaches, and other pest insects every month. In tropical countries, many people welcome geckos in their homes because they eat annoying and disease-carrying bugs. Geckos provide natural pest control without the need for chemical sprays. Some farmers even encourage geckos in their fields to control crop-damaging insects!
Geckos inspire amazing technology! Scientists studying gecko toe pads have created new types of adhesives that stick and unstick on command. Gecko-inspired robots can climb walls and ceilings for search and rescue missions. Medical researchers are developing gecko-inspired bandages that stick to wet surfaces inside the body. The U.S. military has even tested gecko-inspired climbing paddles that let soldiers scale walls!
Geckos are important parts of food webs! They eat insects and are eaten by snakes, birds, and larger lizards. On islands, geckos are often among the most common vertebrates and play key roles in the ecosystem. Some geckos also pollinate flowers and spread seeds when they eat fruit and nectar. Removing geckos from an ecosystem can have ripple effects throughout the food web!
Many gecko species need protection! Habitat destruction threatens geckos worldwide, especially in tropical forests. The pet trade puts pressure on some wild populations. Island geckos are especially vulnerable because they live in small, isolated habitats. Several gecko species are found nowhere else on Earth and could disappear if their habitats are destroyed. Protecting tropical forests and islands helps protect these fascinating wall-walking lizards!