Gecko

Geckos are small, meat-eating 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) long. They are the most common group of lizards, with almost 2,000 different kinds.

Most geckos make chirping or clicking sounds to talk to each other, and Tokay geckos are known for their loud mating calls. Unlike many lizards, geckos are usually active at night and have great night vision, which helps them see in dim light much better than human eyes. Many geckos can climb smooth and upright surfaces thanks to special toe pads. Some even live inside homes, where they help eat insect pests like moths and mosquitoes.

Etymology

The word "gecko" comes from the Malay language. It started from a Javanese word that sounds like "tokek." This copies a sound some geckos make, like the Tokay gecko. The sound later became the word "gecko" in English and Neo-Latin.

Common traits

Geckos are like other reptiles because they cannot make 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 sometimes. 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. 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. 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. These bumps help the gecko stay clean.

One type of gecko from Madagascar, called the mossy leaf-tailed gecko, has colors that help it hide. Its skin looks like tree bark, making it hard to spot. It also has special skin flaps 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 has seven families. These families include about 125 genera of geckos. Some geckos are snake-like and have no legs; these are called pygopods.

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

Legless lizards called blind lizards, from the family Dibamidae, are sometimes thought to be related to geckos. But recent studies show they are not.

Evolutionary history

Some lizards from long ago are thought to be early relatives of geckos. One of these is Eichstaettisaurus from Germany. Another is Norellius from Mongolia. The oldest gecko fossils are from Myanmar, found in Burmese amber. These fossils are about 100 million years old and are from the mid-Cretaceous period. They have sticky pads on their feet, like modern 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 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.

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 old Greek stories, the goddess Demeter once spilled her drink on a boy named Ascalabus. This turned him into a colorful gecko. This is how people long ago explained the gecko's appearance.