Gecko

Geckos are small, mostly carnivorous lizards found on every continent except Antarctica. They belong to the suborder Gekkota and live in warm climates. Geckos range from 1.6 to 67 centimetres (0.6 to 26.4 inches) in length and are the most species-rich group of lizards, with nearly 2,000 different species.

Most geckos make chirping or clicking sounds to communicate, and Tokay geckos are famous for their loud mating calls. Unlike many lizards, geckos are usually nocturnal and have excellent night vision, which helps them see in low light much better than human eyes. Many geckos can climb smooth and vertical surfaces thanks to special toe pads, and some even live inside homes where they help eat insect pests like moths and mosquitoes.

Etymology

The word "gecko" comes from a language called Malay, which got it from Javanese. In Javanese, there is a word that sounds like "tokek," which copies the sound some geckos make, like the Tokay gecko. This sound then became the word "gecko" in English and Neo-Latin.

Common traits

Geckos are like other reptiles because they cannot create their own body heat. Their body temperature changes with the environment. They need to stay warm to move, eat, and have babies.

All geckos lose their skin from time to time. For example, leopard geckos shed every two to four weeks. Moisture helps them shed their skin. When they start to shed, geckos pull off their loose skin and eat it. Baby geckos shed more often, about once a week, but adult geckos shed once every one to two months.

Many geckos can stick to surfaces using special pads on their toes. These pads help them climb without using liquids. Scientists used to think these pads worked by very weak forces, but new studies show they may work by electric forces instead. These toe pads can clean themselves and usually remove dirt after a few steps. Humidity can help geckos stick better, but they have trouble sticking when fully underwater.

Gecko toes can bend in ways human toes cannot, which helps them peel their toes off surfaces bit by bit. Each square millimetre of a gecko’s footpad has about 14,000 tiny hair-like structures. Each of these hairs has many even smaller tips, allowing geckos to stick to surfaces with very little force. These tiny structures, along with natural oils from the gecko’s body, help them attach and detach easily.

Main article: Synthetic setae

Skin

Gecko skin looks special because it has tiny, hair-like bumps all over it. These bumps help the gecko stay clean and protect it from tiny harmful germs.

One type of gecko from Madagascar, called the mossy leaf-tailed gecko, has colors that help it hide. Its skin looks like tree bark with lichen and moss, making it hard to spot. It also has special skin flaps that it uses to blend in with trees.

Teeth

Geckos can replace all of their about 100 teeth every 3 to 4 months. Next to each grown tooth, a new small tooth grows from special cells in the mouth. Unlike many other lizards, geckos do not have teeth on the roof of their mouths. Their teeth are attached to the inside of their jaw bones, which is a common feature in lizards.

Taxonomy and classification

The suborder Gekkota is divided into seven families, containing about 125 genera of geckos, including the snake-like (legless) pygopods.

• Family Carphodactylidae
• Family Diplodactylidae
• Family Eublepharidae
• Family Gekkonidae
• Family Phyllodactylidae
• Family Pygopodidae
• Family Sphaerodactylidae

Legless lizards of the family Dibamidae, also referred to as blind lizards, have occasionally been counted as gekkotans, but recent studies suggest otherwise.

Evolutionary history

Several species of lizard from the late Jurassic have been considered early relatives of geckos, the most prominent and most well supported being the arboreal Eichstaettisaurus from the late Jurassic of Germany. Norellius from the early Cretaceous of Mongolia is also usually placed as a close relative of geckos. The oldest known fossils of modern geckos are from the mid-Cretaceous Burmese amber of Myanmar (including Cretaceogekko), around 100 million years old, which have adhesive pads on the feet similar to those of living geckos.

Species

There are over 1,850 kinds of geckos found all over the world. Some well-known geckos include:

• The western banded gecko, which lives in the southwestern United States and northwest Mexico.
• The leopard gecko, a popular pet that doesn’t stick to glass.
• The Tokay gecko, a large gecko from Southeast Asia known for its loud calls.
• The common house gecko, which likes to live near people in warm places.
• The dwarf gecko, the smallest lizard in the world, found in the Caribbean Islands.

Reproduction

Most geckos lay a small group of eggs. Some geckos can have babies alive without a male, and a few can make babies all by themselves. Geckos have many ways to decide if their babies will be male or female, like the temperature or special things in their bodies.

Madagascar day geckos have a special way to show they are ready to have babies. Males make a waxy substance from their legs and move their heads and flick their tongues quickly to show interest to females.

Mythology

In ancient Greek stories, the goddess Demeter was very upset one day. She spilled her drink on a young boy named Ascalabus. Because of this, he changed into a colorful gecko. This is how people long ago explained why geckos look the way they do.