Shedding or molting
All geckos shed their skin at fairly regular intervals, with species differing in timing and method. Leopard geckos will shed at about two- to four-week intervals. The presence of moisture aids in the shedding. When shedding begins, the gecko will speed the process by detaching the loose skin from its body and eating it.
Gecko toes have special adaptations that allow them to adhere to most surfaces without the use of liquids or surface tension. About 60% of gecko species have adhesive toe pads; such pads have been gained and lost repeatedly over the course of gecko evolution.Adhesive toepads evolved independently in about 11 different gecko lineages and were lost in at least 9 lineages.
The spatula-shapedsetae arranged in lamellae on gecko footpads enable attractive van der Waals' forces between the β-keratin lamellae/setae/spatulae structures and the surface. These van der Waals 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. The setae on the feet of geckos are also self-cleaning and will usually remove any clogging dirt within a few steps. Teflon, which has very low surface energy, is more difficult for geckos to adhere to than many other surfaces.
Increasing humidity typically fortifies gecko adhesion, even on hydrophobic surfaces, yet is reduced if completely immersed in water. The role of water in that system is under discussion, yet recent experiments agree that the presence of molecular water layers (water molecules carry a very large dipole moment) on the setae as well as
on the surface increase the surface energy of both, therefore the energy gain in getting these surfaces in contact is enlarged, which results in an increased gecko adhesion force. Moreover, the elastic properties of the b-keratin change with water uptake. Friction experiments with gecko toes—torn parallel to surfaces—have shown to be influenced also by electrostatic forces.
Gecko toes seem to be "double jointed", but this is a misnomer and is properly called digital hyperextension. Gecko toes can hyperextend in the opposite direction from human 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 most of the time, because the margin for error is great depending upon the surface roughness, and therefore the number of setae in contact with that surface.
Use of small van der Waals attraction force requires very large surface areas: every square millimeter of a gecko's footpad contains about 14,000 hair-like setae. Each seta has a diameter of 5 μm. Human hair varies from 18 to 180 μm, so a human hair could hold between 12 and 1300 setae. Each seta is in turn tipped with between 100 and 1,000 spatulae. Each spatula is 0.2 μm long (one five-millionth of a meter), or
just below the wavelength of visible light.
The setae of a typical mature 70 g (2.5 oz) gecko would be capable of supporting a weight of 133 kg (293 lb): each spatula can exert an adhesive force of 5 to 25 nN. The exact value of the adhesion force of a spatula varies with the surface energy of the substrate to which it adheres. Recent studies  have moreover shown that the component of the surface energy derived from long-range forces, such as van der Waals forces, depends on the material's structure below the outermost atomic layers (up to 100 nm beneath the surface); taking that into account, the adhesive strength can be inferred.
Recent studies have also revealed that apart from the setae, phospholipids—fatty substances produced naturally in their bodies—also come into play. These lipids lubricate the setae and allow the gecko to detach its foot before the next step.
Biomimetic technologies designed to mimic gecko adhesion could produce reusable self-cleaning dry adhesives with many applications. Development effort is being put into these technologies, but manufacturing synthetic setae is not a trivial material design task.
Uroplatus fimbriatus clinging to glass
Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 to 60 cm (0.64 to 24 inches). Most geckos cannot blink, but they often lick their eyes to keep them clean and moist. They have a fixed lens within each iris that enlarges in darkness to let in more light.
Geckos are unique among lizards in their vocalizations. They use chirping sounds in social interactions with other geckos. They are the most species-rich group of lizards, with about 1,500 different species worldwide. The New Latin gekko and English "gecko" stem from the Indonesian-Malay gēkoq, which is imitative of the sound the animals make.
All geckos, excluding the Eublepharidae family, lack eyelids and instead have a transparent membrane, which they lick to clean.Nocturnal species have an excellent night vision; their color vision is 350 times more sensitive than human color vision. The nocturnal geckos evolved from diurnal species which had lost the eye rods. The gecko eye therefore modified its cones that increased in size into different types both single and double. Three different photopigments have been retained and are sensitive to UV, blue, and green. They also use a multifocal optical system that allows them to generate a sharp image for at least two different depths.
Most gecko species can lose their tails in defense, a process called autotomy. Many species are well known for their specialized toe pads that enable them to climb smooth and vertical surfaces, and even cross indoor ceilings with ease. Geckos 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 (for example the house gecko) become part of the indoor menagerie and are often welcomed, as they feed on insects, including moths andmosquitoes. Unlike most lizards, geckos are usually nocturnal.
The largest species, the kawekaweau, is only known from a single, stuffed specimen found in the basement of a museum in Marseille, France. This gecko was 60 cm (24 in) long and it was likely endemic to New Zealand, where it lived in native forests. It was probably wiped out along with much of the native fauna of these islands in the late 19th century, when new invasive species such as rats and stoats were introduced to the country during European colonization. The smallest gecko, the Jaragua sphaero, is a mere 1.6 cm long and was discovered in 2001 on a small island off the coast of the Dominican Republic.
Gold dust day gecko
Geckos are selectively bred. Geckos occur in various patterns and colors, and are among the most colorful lizards in the world. Some species can change colour and may be lighter in colour at night. Some species are parthenogenic, which means the female is capable of reproducing without copulating with a male. This improves the gecko's ability to spread to new islands. However, in a situation where a single female gecko populates an entire island, the island will suffer from a lack of genetic variation within the geckos that inhabit it. The gecko's mating call sounds like a shortened bird chirping which attracts males, when they are nearby. Like other reptiles, geckos are ectothermic, producing very little metabolic heat. Essentially a gecko's body temperature is dependent on its environment. Also, in order to accomplish their main functions—such as locomotion, feeding, reproduction, etc.—geckos must have a relatively elevated temperature.
Oligocene-era gecko trapped inamber
Taxonomy and classification
The infraorder Gekkota is divided into seven families, containing numerous genera of gecko species.
Close-up of the underside of a gecko's foot as it walks on vertical glass
Geckos are polyphyodonts and able to replace each of their 100 teeth every 3 to 4 months. Next to the full grown tooth there is a small replacement tooth developing from theodontogenic stem cell in the dental lamina. The formation of the teeth is pleurodont; they are fused (ankylosed) by their sides to the inner surface of the jaw bones. This formation is common in all species in the order Squamata.
- By far the most common family is the Gekkonidae. These 1000 plus species make up over a third of the world’s geckos and will be the ones you are most familiar with, including the house gecko.
- Gecko eggs take about 40-60 days to hatch. After that it will be a year before they are mature and ready to meet and mate. On average a gecko will live up to 10 years but a number of species will live to double that. The longest recorded lifespan in captivity is 27 years. So, if you are ten right now and want a gecko as a pet, you must realise that you could still have it when you are thirty! And don’t think that Mom will look after it because she might not like your gecko quite as much as you!
Pores on the skin are often used in classification.
Species of geckos
More than 1,650 species of geckos occur worldwide, including these familiar or notable species:
Coleonyx variegatus, the western banded gecko, is native to the southwestern United States and northwest Mexico.
Cyrtopodion brachykolon, the bent-toed gecko, is found in northwestern Pakistan; it was first described in 2007.
Eublepharis macularius, the leopard gecko, is the most common gecko kept as a pet; it does not have adhesive toe pads and cannot climb the glass of a vivarium.
Gehyra mutilata (Peropus mutilatus), the stump-toed gecko, is able to vary its color from very light to very dark to camouflage itself; this gecko is at home in the wild, as well as in residential areas.
Gekko gecko, the Tokay gecko, is a large, common, Southeast Asian gecko known for its aggressive temperament, loud mating calls, and bright markings.
Hemidactylus is genus of geckos in which there are many varieties.
Hemidactylus frenatus, the Common house gecko, thrives around people and human habitation structures in the tropics and subtropics worldwide.
Hemidactylus garnotii, the Indo-Pacific gecko, is found in houses throughout the tropics, and has become an invasive species of concern in Florida and Georgia in the US.
Hemidactylus mabouia, the Tropical house gecko, Afro-American house gecko or Cosmopolitan house gecko, is a species of house gecko native to sub-Saharan Africa and also currently found in North, Central and South America and the Caribbean.
Hemidactylus turcicus, the Mediterranean house gecko, is frequently found in and around buildings, and is an introduced species in the US.
Lepidodactylus lugubris, the mourning gecko, is originally an East Asian and Pacific species; it is equally at home in the wild and residential neighborhoods.
Pachydactylus bibroni, Bibron's gecko, is native to southern Africa; this hardy arboreal gecko is considered a household pest.
Phelsuma laticauda, the gold dust day gecko, is a diurnal gecko; it lives in northern Madagascar and on the Comoros. It is also an introduced species in Hawaii.
Mediterranean house gecko
Dwarf yellow-headed gecko, in Dar es Salaam, Tanzania
Number of gecko species (left, red) and number of gecko species described per year (right, purple). The number excludes the ~50 species of pygopods. Based on species numbers from the Reptile Database
For the external links , refrences click here to read the full wikipedia article
Why Leopard Geckos Make Great Pets
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The Amazing Gecko: 20 Interesting Facts about the World’s Most Species-Rich Lizard
- The gecko is an extraordinary lizard, a triumph of both adaptation and diversity. Out of the 5,600 species of lizard on the planet, over 1,500 belong to the gecko infraorder called Gekkota. So, what is so interesting about a line of lizards which is, apparently, so ubiquitous? Here are 20 interesting facts about the gecko, as well as some amazing pictures of species that you may not have come across before.
- Geckos can vary greatly in length. The smallest (Jaragua sphaero) is tiny, just under two centimeters in length. However, some species can grow up to 60 centimeters. The largest ever discovered, the Kawekaweau from New Zealand, is sadly now extinct.
- Most species of geckos are nocturnal. They have a lens in each iris that enlarges in darkness, making their eyes over 350 times more sensitive to light than ours.
- The name comes from the Indonesian Malay language – gekoq. Even in this language it is not a real word, but an imitation of the chirrups that the gecko makes when interacting with others of its species.
- You will not find a gecko in possession of eyelids. They have a transparent membrane instead. So that they can keep it clean you will see geckos lick their eyes. No one really knows if they can sense this or the membrane is insensitive enough for them to lick without feeling a thing. We know it doesn’t hurt, however: they wouldn’t do it otherwise!
- If they are defending themselves, most gecko species can lose their tails. The scientific name for this is autotomy, which is from the Greek for self amputation. Many people think the gecko loses its tail as that is the part most likely to be grabbed by a predator. While it may be the obvious target, the reality is that when the gecko sheds its tail, it continues to wriggle about. This hopefully is enough of a distraction that the gecko can escape the predator that wants to make it their lunch.
- Most species of gecko have to have their tail pulled in order to shed it. However, a number of species, especially those who may be attacked by ants, are able to get rid of their tail at will. The tail can in many cases grow back. However, this replacement is made of cartilage and does not have any of the bone structure of the original.
- When a gecko sheds its tail, many will return later to see if it is still there. If it is then they will eat it. This is because the gecko uses part of its tail to store nutrients so that it can get through lean times when food is scarce.
- Unlike many species, the gecko thrives around humans. In warm regions of the world the arrival of gecko in to the home is greeted as a sign of good luck as they can help rid the house of unwelcome insects – they love a bit of mosquito for supper.
- Geckos have highly specialized toe pads. This enables them, much to the amazement of human onlookers, to climb vertical surfaces (as long as they are smooth). They can even cross ceilings.
- Geckos can stick to walls and ceilings because of the attractive nature of intermolecular van der Waals forces. Van der Waals forces include attractions and repulsions between atoms, molecules, and surfaces, as well as other intermolecular forces.
- Geckos also secrete a liquid from a special gland. The gland enables them to excrete and absorb liquid according to the surface that they are on at any given time. In this way the liquid allows for maximum adherence to that surface.
- Geckos do not like Teflon. It has a low surface tension and as a result geckos find it difficult to stick to Teflon for any amount of time or effectively. Fortunately their natural surroundings are usually Teflon-free! The gecko has outgrowths of tissue on their footpads called setae. This word derives from the Latin for bristle – and you can see why. Small and hair like, the ones that you can see branch out even further in to what are called nanometer scale projections. Tiny as they are, they play a vital role in the gecko’s climbing skills.
- As you have already seen, geckos come in a huge variety of patterns and colors. Some of them can change their color and others become lighter at night. Geckos are parthenogenic. So, say for example, a female gecko washes up on a gecko-free island she can reproduce without mating with a male. However, when this happens these geckos will have a lack of genetic diversity which could mean shorter life spans and greater threat from diseases.
- Geckos like to shed their skins – a lot. Most species will do it at regular intervals, especially when they are around good water supplies. The leopard gecko will shed every two to four weeks. However, the gecko is a waste-not, want-not species and will eat the skin it sheds for the nutrients it contains.
- The Ptychozoon (above) is also known as the Flying Gecko or even the Parachute Gecko. They have evolved so they can conceal themselves against the side of trees but this is not the most interesting of their evolutionary traits. Thanks to webs situated around their body they can leap in to the air and open these flaps which it then uses to control its fall. It can ‘fly’ up to 60 meters and when nearing the ground it swoops, so landing softly.
- There are seven divisions (known as families) in the Gekkota infrorder. This includes the Pygopodidae, which have long and elegant bodies but no forelegs, with only vestigial hind legs. They may look like snakes but they are not. They have unforked tongues for a start – not to mention external ear holes.
Giant Leaf-tailed Gecko - Uroplatus fimbriatus
Tokay Gecko - Gecko gecko
Common Scaly Lizard - Paradelma orientalis
Geckos and skinks
courtesy to : www.teara.govt.nz/en/diagram/13511/geckos-and-skinks
There are a number of visible differences between New Zealand’s two lizard families.
Leopard Gecko - Eublepharis macularius
Fish-Scaled Gecko - Geckolepis sp.
Mauritius Ornate Day Gecko - Phelsuma ornata
Northern Leaf-tail Gecko - Saltuarius cornutus
William's Dwarf Gecko (aka Electric Blue Gecko) - Lygodactylus williamsi
Spearpoint Leaf-tailed Gecko - Uroplatus ebenaui
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