Leopard gecko

The leopard gecko (Eublepharis macularius) is a crepuscular ground-dwelling lizard naturally found in the deserts of Asia and throughout Pakistan, to the northwestern parts of India. Unlike most geckos, leopard geckos possess movable eyelids. It has become a well-established and popular pet in captivity.

Taxonomy

Leopard geckos were first described as a species by zoologist Edward Blyth in 1854 as Eublepharis macularius.^[1] The generic name Eublepharis is a combination of the Greek words Eu (good), and blephar (eyelid), as having eyelids is the primary characteristic that distinguishes members of this subfamily from other geckos, along with a lack of lamellae, bumpy skin, and nocturnal behavior.^[2] The specific name, macularius, derives from the Latin word macula meaning "spot" or "blemish", referring to the animal's natural spotted markings.

Leopard geckos are related to many different geckos including the African fat-tailed gecko. There are four species however that are exceptionally closely related to the leopard gecko, one of which was previously included as a subspecies of leopard gecko:

• Eublepharis angramainyu (Anderson & Leviton 1966)^[3]
• Eublepharis fuscus (Börner 1981)^[3]
• Eublepharis hardwickii (Gray 1827)^[3]
• Eublepharis turcmenicus (Darevsky 1977)^[3]

In addition, there are five subspecies of leopard gecko:

• Eublepharis macularius macularius,^[1] the nomitive species
• E. m. fasciolatus (Günther 1864),^[4]
• E. m. montanus (Börner 1976)^[5]
• E. m. smithi (Börner 1981)^[5]
• E. m. afghanicus (Börner 1976)

Distribution

The native habitat of the leopard gecko is the rocky, dry grassland and desert regions of south-Asian Afghanistan, Pakistan, north-west India, and some parts of Iran. Winter temperatures in these areas can be quite low, below 10 °C (50 °F), forcing the animals underground into semi-hibernation, called brumation, living on fat reserves. Leopard geckos are crepuscular reptiles; they are limited to the burrows during the day but become active at dawn and dusk when the temperature is favorable.^[6] These geckos are solitary, and do not usually live with other animals.^[7]

Diet

Leopard geckos feed on crickets, waxworms, mealworms, super worms, pinky mice, although these have fatty livers, and other insects. In captivity, most individuals will prefer hunting food themselves. The majority of captive leopard geckos will also refuse to eat dead prey (unless you force feed them.) Crickets are the most common food source to give them as they can hunt them in their enclosure the way they would in their natural environment. When food is scarce in the desert, they can rely on their ability to store excess fat in their tails. Sufficient calcium and vitamin D3 is also very important for their diet: How they obtain it in the wild is still unknown, although they likely receive this from their varied prey of moths, spiders, ants, and other insects. In captivity, it is near impossible to completely duplicate the diet they will have in the wild, so the most nutritious insects known are offered, usually dusted with a fine calcium powder with added vitamin D3 and sometimes gut loaded by feeding. Also, their keen sense of smell and sight allows them to search for food in the wild, they will stalk their prey just like an actual leopard will, move their tail, and then strike when they are satisfied.^[7]

Characteristics

Leopard geckos are large for a gecko. Hatchlings tend to be 6.5 to 8.4 cm (2.6 to 3.3 inches) in length and weighing about 3 grams while the adult geckos are about 20.5 to 27.5 cm (8.1 to 11 inches) in length and weigh about 45 to 65 grams.

Those found in the wild typically have a darker, dull, and drab coloration than those kept in captivity as pets. Those in captivity generally have an assortment of skin colors and patterns. The skin of a leopard gecko is very durable, which provides protection from the rough sand and rocky hills terrain of their dry environment. Their dorsal side is covered with small bumps, which gives a rough texture and appearance while their ventral side is thin, transparent, and smooth. Like all reptiles, leopard geckos shed their skin. In the few days before the shedding, the skin will turn color to a translucent whitish gray.^[8] Adults shed an average of once a month, while juveniles will sometimes shed twice as much.^[9] The gecko will eat its old skin after shedding, revealing a brighter colored one. There are two theories of why leopard geckos do this. One is that in the wild leopard geckos eat their shed skin so there is no trace that the leopard gecko was there.^[8] The other theory is that eating the shed skin is a means for obtaining protein and other vitamins for growth.^[9]

Leopard geckos are ectothermic. They absorb warmth and energy during the day as they are sleeping, so they can hunt and digest food at night. In addition, they have short legs, which enable them to be quick and agile while their small nails allow them to climb twigs and rocks. Leopard geckos have openings on either side of their head as ears. A tympanic membrane covers and protects it. They use their ears to locate their prey. Healthy leopard geckos have thick, fleshy tails; a thin tail is an indication that the gecko is not healthy and may be lacking nutrition. Although, when in captivity, the tail can be fattened by the feeding of waxworms (wax moth larvae), these worms are typically too fatty for the gecko to get the nutritional value it needs. They can also be fed "pinkys", a one day old mouse to fatten up the tail, but again, these are very low in nutritional value.^[10] Breeders recommend coating crickets in a nutritional powder before serving them either live or dead. Leopard geckos' thick tails can regenerate when lost; however, the regenerated tails appear stumpy and never have the same appearance as the original tail.^[7]

Unlike many other geckos, but like other Eublepharis, their toes do not have adhesive lamellae, so they cannot climb smooth vertical walls.

Teeth

Leopard geckos are polyphyodonts and able to replace each of their 100 teeth every 3 to 4 months.^[11] Next to the full grown tooth there is a small replacement tooth developing from the odontogenic stem cell in the dental lamina.^[12]

Defense mechanisms

Leopard geckos have predators such as snakes, frogs, foxes and other large reptiles. Their keen sense of hearing and sight help them escape from them during the night. Along with their exceptional sight and hearing abilities, their skin helps camouflage themselves from their predators. Their sense of taste and smell also helps them with survival. The shedding of their skin also removes any scent markers left behind for potential predators to discover. When they feel threatened, startled, or scared, leopard geckos hiss to ward off predators. Also, they stay in underground holes and burrows during the daytime, not only avoid the heat, but to also avoid the risk of getting eaten.^[7]

Leopard geckos also have the ability to voluntarily detach their tails if it is attacked, grabbed by the tail, bitten during copulation, or nipped by another during feeding. This is called caudal autotomy. After autotomy the tail can continue to twitch for as long as 30 minutes, allowing the gecko to escape from its predator.^[13][14] The tail is large and at least in one related species (Christinus marmoratus) it has been reported that the tail-less fleeing gecko makes for a quicker getaway.^[15] Fractures in the tailbone allow the tail to separate easily and rapid vasoconstriction allows the gecko to suffer minimal blood loss. This detaching of the tail causes a high level of stress on the gecko due to the loss of the valuable storage of fat it once had.^[16] It will start to regenerate its tail immediately because it is needed for survival. A lost tail may increase the chance of sickness in the gecko and in some cases kill it, but this is very rare.^[7] Regenerated tails often retain similar colors to the original tail [though there will most likely be a wide variance from the vibrancy and patterns of the original], however they are often smooth and lack the rigid qualities and length of a normal tail. The tail will also be shorter and often fatter than the previous tail.

Sexual dimorphism

Sexual dimorphism is defined as a phenotypic difference between males and females of a species. It can be commonly found in animals, such as the leopard gecko and other reptiles.^[17] It exists in adult males and females, but can be difficult to determine in young geckos. The underside of a gecko truly determines the sex of the gecko. Males have pre-anal pores and hemipenal bulges while females have smaller pores and do not have external bulges.^[7]

Males can determine the sex of other leopard geckos by smelling pheromones on their skin. Males respond to males with aggressive behavior while they demonstrate courtship behavior towards females. Towards other males, the male would raise itself up from the ground, extend his limbs, and arch his back with the swelling of the tongue in aggression. He will then make short dashes and quick, vigorous bites, which frequently lacerate the skin and sometimes severely injure his opponent. Males behave the same way towards females while they are shedding their skin. Before and after the shedding of the skin, the males still express courtship behavior towards the females.^[18]

Reproduction

They are also known to have temperature-dependent sex determination (TSD). Research shows that more females can be produced in predominantly cool temperatures (about 26–30 °C (79–86 °F)) and very warm temperatures (about 34–35 °C (93–95 °F)). It was recorded that males can be produced at the intermediate temperatures (about 31–33 °C (88–91 °F)). Females born in the higher temperatures differed from those who were born in the lower temperatures hormonally and behaviorally. Those born in the warmer temperatures expressed more aggressive behavior.^[19] These are known as "hot females" and are often determined to be infertile.

Leopard geckos will breed typically in the summer. Females can store sperm over the course of their breeding season, so they can produce up to three clutches from one or two copulations, therefore, the male is not needed for reproductive success after the first or second copulation.^[20] Once the female is pregnant, she will need an abundance of calcium for health and to ensure that the eggs calcify properly. She can lay about six to eight clutches, which consists of two eggs in each clutch. They will normally lay two eggs approximately 21 to 28 days after mating. After 45 to 60 days, droplets of moisture will appear on the shell and the shell will begin to shrink and partially collapse. These are indications that the eggs will hatch. Baby leopard geckos will have an "egg tooth", a calcareous tip at the end of its snout to help break their egg shell. Their "egg tooth" will fall off within one to two days. In addition to this, their skin will usually shed within 24 hours of hatching. The leopard gecko hatchling will not be able to eat until after the first shedding.^[7]

Diseases

There are several common diseases that leopard geckos may experience.

• Gastoenteritis or diarrhea is a disease that is caused by a bacterial infection caused by unsanitary conditions. An indication of the disease is that the leopard gecko has watery and/or bloody stool. Normally the stool is dry and well-formed with a small white portion. It is contagious and can be spread easily. Other symptoms of the disease include weight loss, a skinny tail, undigested cricket masses. If it is not treated, the gecko will stop eating, become dehydrated and scrawny, and possibly die.^[7]
• Coccidia causes gastrointestinal problems when protozoan parasites infect the lining of the intestine. It is contagious and can infect other leopard geckos that are in close proximity to the infected one. If untreated, the leopard gecko will stop eating and become sluggish, dehydrated, and anorexic.^[7]
• Metabolic bone disease or MBD is a nutritional deficiency caused by a lack of calcium and vitamin D₃ in the diet. Calcium and vitamin D₃ are critical for proper bone formation during development and for proper calcification of eggs for a pregnant female. Geckos with MBD will experience symptoms such as weakness, bones becoming spongy, deformities in their limbs and spine, twitching or tremors, and a lack of appetite. Recovering from this disease can be very difficult.^[7]
• Anorexia in leopard geckos can be caused by stress, unsanitary conditions, nutritional diseases, or other diseases. Anorexic leopard geckos appear thin, develop an extremely thin tail, become weak and sluggish, stop eating, and usually die if untreated.^[7]
• Dysecdysis is a condition in which a leopard gecko has problems shedding its skin due to poor nutrition, lack of humidity and moisture, and poor care. Incompletely shed skin will appear as dry patches on various areas of the body such as the head, eyes, limbs, and tail. Leopard geckos with this condition may develop eye problems, have difficulty in walking, and noticeable constricting bands of old skin around their limbs. If the condition is not treated, it could lead to infection.^[7]
• Dystocia or "egg-binding" is when a pregnant female cannot expel her eggs. This may occur if the eggs are too large to be passed through the oviduct and cloaca, or because of nutritional factors, an ill or weak female, and other unknown problems. With this condition, the female usually stops eating and becomes weak and lethargic.^[7]
• Stomatitis or mouthrot is when a leopard gecko has swelling around its mouth area with pus or a cheesy-like substance.^[7]
• Pneumonia is a severe respiratory tract infection caused by bacteria in the lungs. Leopard geckos may be susceptible to this if their environment is too cool and humid thus compromising their immune system. Mucus bubbles appear in the nostril area of geckos with pneumonia, and they have difficulty breathing. The problem is usually resolved when the environment temperature rises to about 82 to 85 °F (28 to 29 °C).^[7]
• Sand impactions and prolapse can occasionally occur. This condition may result if a leopard gecko ingests sand or other substrates they live on.^[7]
• Cryptosporidiosis, also known as "crypto", is a highly infectious disease that is often fatal to leopard geckos if not detected and treated in its early stages. Although a definitive diagnosis can be difficult to make, the disease can be recognized by regurgitated food in the enclosure, liquid feces, and consequently a very thin body and tail (also called "pencil tail"). Although the success rate is still low there are experimental treatments for crypto that can be successful, but involve a painstaking process. Because of this and the difficulty of diagnosing the disease, many suspected infected pet leopard geckos are euthanized.^[21]

Leopard geckos as pets

Leopard geckos are one of the most popular reptile pets. They are possibly the first domesticated lizard species.^[22][23] Their small size, robustness, and relatively easy care makes them a good "beginner" reptile pet.^[24] They breed easily in captivity, so most sold today are captive-bred rather than wild-caught. Many morphs—color or pattern variations, and occasionally size variations—have been bred. Some of the morphs include three different strains of albino, patternless, blizzard, jungle, hypomelanistic, tangerine, giant, and snow. Since many of the morphs are unrelated gene sequences, various combinations, such as patternless albino and mack snow albino, have also been bred. Patternless, hypomelanistic, and blizzard morphs primarily involve the reduction or loss of dark spots. Giant is a size morph, giants are considerably larger than normal leopard geckos. Jungle morphs involve a change in the arrangement or pattern of dark areas. Snow morphs typically have normal dark spots, but little or no yellow pigment. Tangerine morphs have an orange pigment on part of their body, typically the head and/or tail.

References

External links

Wikimedia Commons has media related to Leopard gecko.

Wikispecies has information related to: Eublepharis macularius

• Leopard Gecko Wiki – Great resource for Leopard Gecko information
• Leopard Gecko Care and Information
• Leopard Gecko Caresheet
• Leopard Gecko Pedigree Database
• "Breeding of the Leopard Gecko" (video). marthastewart.com.