gecko

 

(gĕk'ō) , small or medium-sized lizard of the family Gekkonidae. The more than 300 species are distributed throughout the warm regions of the world, mostly in the Old World. Despite folklore to the contrary, their bite is not poisonous. Many species are arboreal, while others inhabit human dwellings. Most lack movable eyelids and have characteristic pads on the undersides of their feet that enable them to cling to smooth surfaces and to run upside down on ceilings. The pads contain microscopic backward-projecting hairs covered by tiny pads that may generate an adhesive force through van der Waals attractions (see intermolecular forces). Geckos are unique among lizards in that they possess voices, and different species make characteristic sounds. They feed on small animals, chiefly insects. Nearly all lay eggs. The largest species is the 14-in. (35.5-cm) tokay, Gekko gecko, of SE Asia. The wall gecko, Tarentola mauritanica, of the Mediterranean region is commonly seen basking by day on walls and rocks; it hunts by night. There are two native species in the United States, the leaf-fingered gecko (Phyllodactylus tuberculatus) of extreme S California and Baja California, and the banded, or ground, gecko (Coleonyx variegatus) of the deserts of the SW United States and N Mexico. The latter is a ground-dwelling form and lacks foot pads. In Florida there are several introduced West Indian species as well as the widely distributed Turkish gecko, Hemidactylus turcicus, originally from Africa. Geckos are classified in the phylum Chordata, subphylum Vertebrata, class Reptilia, order Squamata, family Gekkonidae.

Geckos
Gold dust day gecko
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Squamata Suborder: Lacertilia Family: Gekkonidae Gray, 1825
Subfamilies
Aeluroscalabotinae Eublepharinae Gekkoninae Teratoscincinae Diplodactylinae

Geckos are small to average sized lizards belonging to the family Gekkonidae which are found in warm climates throughout the world. Geckos are unique among lizards in their vocalizations, making chirping sounds in social interactions with other geckos. There are 1,196 different species of geckos. [1] The name stems from the Malay word gekoq, imitative of its cry. Geckos are unusual in other respects as well. Most geckos have no eyelids and instead have a transparent membrane which they lick to clean. Many species will, in defense, expel a foul-smelling material and feces onto their aggressors. Many species have specialized toe pads that enable them to climb smooth vertical surfaces and even cross indoor ceilings with ease. These antics are well-known to people who live in warm regions of the world where several species of geckos make their home inside human habitations. These species (for example the house gecko) become part of the indoor menagerie and are seldom really discouraged because they feed on insect pests.

Common traits

Geckos come in various colors and patterns. Some are subtly patterned, and somewhat rubbery looking, while others can be brightly colored. Some species can change color to blend in with their surroundings or with temperature differences.

Some species are parthenogenic, the females capable of reproducing without copulating with a male. This improves the gecko's ability to spread to new islands.

The toes of the gecko have attracted a lot of attention, as they adhere to a wide variety of surfaces, without the use of liquids or surface tension. Recent studies of the spatula tipped setae on gecko footpads demonstrates that the attractive forces that hold geckos to surfaces are van der Waals interactions between the finely divided setae (almost 500,000 Setae on each foot, and each of these tipped with between 100 and 1,000 spatulae) and the surfaces themselves. Each seta is 2 diameter of human hair long i.e 100 millionth of meter and each spatulae is 200 billionth of meter long, just below wavelength of visible light.^[1] These kinds of interactions involve no fluids; in theory, a boot made of synthetic setae would adhere as easily to the surface of the International Space Station as it would to a living room wall, although adhesion varies with humidity and is dramatically reduced under water, suggesting a contribution from capillarity.^[2] The setae on the feet of geckos is also self cleaning and will usually remove any clogging dirt within a few steps.^[3][4]

Geckos' toes seem to be "double jointed", but this is a misnomer. Their toes actually bend in the opposite direction from our fingers and toes. This allows them to overcome the van der Waals force by peeling their toes off surfaces from the tips inward. In essence, this peeling action alters the angle of incidence between millions of individual setae and the surface, reducing the van der Waals force. Geckos' toes operate well below their full attractive capabilities for most of the time. This is because there is a great margin for error depending upon the roughness of the surface, and therefore the number of spatulae in contact with that surface. If a typical mature 70g gecko had every one of its spatulae in contact with a surface, it would be capable of holding aloft a weight of 133 kg:^[5] each spatula can exert an adhesive force of 10 nN.^[2]

The family Gekkonidae is divided into five subfamilies, containing numerous genera of gecko species. Many geckos are kept as pets and will eat various kinds of insects and sometimes fruit.

Common species of gecko

• Bibron's gecko, Pachydactylus bibroni — Native to Southern Africa, this hardy arboreal gecko is relatively common as a pet.
• Crested gecko, Rhacodactylus ciliatus — Believed extinct until re-discovered in 1994. Gaining in popularity as a pet. Unlike most other geckos, it prefers room temperature and is omnivorous.
• Crocodile gecko or Moorish gecko (due to their crocodile like looks.), Tarentola mauritanica — Crocodile geckos are very strong and heavily built for their size usually growing up to 15.24 cm (6 in). They are commonly found in the Mediterranean region from the Iberian Peninsula and southern France to Greece and northern Africa. Their most distinguishing characteristic is their pointed head and spiked skin with their tail resembling that of a crocodile's.
• Cyrtopodion brachykolon; commonly known as "bent-toed gecko", found in north-western Pakistan.
• Gargoyle gecko, Rhacodactylus auriculatus — commonly known as the New Caledonian bumpy gecko or gargoyle gecko.
• Gold dust day gecko (Phelsuma laticauda laticauda (Boettger, 1880) (syn. Pachydactylus laticauda Boettger, 1880)) is a diurnal subspecies of geckos. It lives in northern Madagascar and on the Comoros.
• Golden gecko, Gekko ulikovskii — native to the warm rainforests of Viet nam.
• House gecko, Hemidactylus frenatus — A species that thrives around man and human habitation structures in the tropics and subtropics world wide.
• Indo-Pacific gecko, Hemidactylus garnotii — Also known as a fox gecko because of its long, narrow snout. This species is found in houses throughout the tropics. This gecko may eat leafcutter ants.
• New Caledonian giant gecko, Rhacodactylus leachianus — first described by Cuvier in 1829, is the largest of the Rhacodactylus geckos.
• Leopard gecko, Eublepharis macularius — The most common gecko kept as a pet is the leopard gecko, which does not have toe pads with setae, but rather claws. These enable it to more easily climb on rough surfaces like tree bark. This gecko cannot climb the glass of a terrarium. The leopard gecko tends to be docile and calm. This gecko can eat butterworms, cockroaches, crickets, mealworms, waxworms, and superworms.
• Mediterranean gecko, Hemidactylus turcicus — residential and wild, introduced species (USA).
• Mourning gecko, Lepidodactylus lugubris — This species is equally at home in the wild as in residential neighborhoods. Found in Hawaii, it may have been an early Polynesian introduction. A parthenogenic species. There is a report from Hawaii of someone having seen a larger gecko of this type eating a smaller one (or rather, running away from view with a smaller gecko halfway out of its mouth) on two occasions.
• Ptychozoon, — a genus of arboreal gecko from Southeast Asia, known as Flying Geckos or Parachute Geckos, has wing-like flaps from the neck to the upper leg, to help it conceal itself on trees and provide lift while jumping.
• Stump-toed gecko, Gehyra mutilata (Peropus mutilatus) — This gecko, commonly referred to as a Gheckl, can vary its color from very light to very dark to blend into a background. At home in the wild as well as in residential neighborhoods.
• Tree gecko, Hemiphyllodactylus typus — Tree geckos are forest dwellers.
• Tokay gecko, Gekko Gecko — a large, common, Southeast Asian gecko known for its aggressive temperament, loud mating calls, and bright markings.
• Western banded gecko, Coleonyx variegatus — Native to southwestern United States and northwest Mexico.

In culture

• In the past few years, geckos have entered into the consciousness of the USA as the advertising icon for the insurance company GEICO, whose advertisements feature an animated anthropomorphic gecko (of the Phelsuma genus) that speaks English with an East London accent.
• Gex is an anthropomorphic, wise-cracking gecko and the protagonist of the GEX video game series.
• The Pokémon Treecko, and its evolved forms Grovyle and Sceptile are based on the gecko, and so is the Neopet Techo.
• The Gold dust day gecko is the un-official Hawaiian state reptile.
• A gecko called Geronimo features in the book My Family and Other Animals by the celebrated naturalist Gerald Durrell.
• Edgar, a character from the webcomic Pandect is an Ace of Blue and White geckos. He is possibly a piebald blue gecko.
• The current mascot of SUSE Linux distribution is a gecko called Geeko, also known as the "SUSE Lizard", but is a Chameleon for the shape.
• In the popular manga One Piece, the shichibukai Gecko Moria's animal theme is a gecko.
• Gecko can be seen on the "bigger" crown of King Julien in the animated movie Madagascar.

Gallery

A Mediterranean gecko in Texas (USA)	A gecko of the genus Cnemaspis from the Western Ghats	A Hemidactylus gecko	Close up of Hemidactylus claws
Leopard gecko (Juvenile)	Northland Green Gecko, New Zealand	Tokay gecko	Leaf Tailed Gecko
Bottom view of a gecko	Small Gecko in L'Escala, Spain. Believed to be a Moorish/Crocodile Gecko

See also

• Geckel

References

• Forbes, Peter (4th Estate, London 2005) 'The Gecko's Foot - Bio Inspiration: Engineered from Nature' ISBN 0-00-717990-1 in H/B

http://www.lclark.edu/~autumn/dept/geckostory.html

External links

• Photo Gallery of Various Gecko Species
• Comprehensive leopard gecko information
• Gecko Resource Forums
• Comprehensive Gecko Care Information
• Global gecko association site with pictures, caresheets, species list
• Leopard Gecko Care
• Josh Ellis and Katie Francis
• Leopard Gecko Care/Breeder
• Gecko anatomy picture
• The Gecko's Foot
• Artificial Gecko feet for a Spiderman suit (BBC 2007-08-28)cdo:Ciēngzh-yue:檐蛇

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