Rhacodactylus Leachianus Gecko: Biology, Behavior, and Conservation

The Rhacodactylus Leachianus gecko, also known as the Leachianus gecko, is a fascinating species native to New Caledonia.

These geckos can grow up to 30 centimeters in length, making them one of the larger species of geckos.

They have a stout body, a flat head, and a long tail, which helps them balance while climbing.

Their skin is smooth and has a distinctive pattern of spots and stripes, allowing them to blend in with their surroundings.

In the wild, Leachianus geckos are primarily nocturnal, spending most of their time foraging for food and resting in dark, humid areas.

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The specific name, leachianus, is in honor of English zoologist William Elford Leach.

Historically, there have been three recognized subspecies of R. leachianus, including the nominotypical subspecies, but no populations are granted subspecies status at the present time.

Locality based morphotypes are used to distinguish populations of R. leachianus instead of subspecies.

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The rhacodactylus leachianus gecko is an impressive creature, and its size is one of its most notable features. It's the largest living gecko species, with some individuals growing up to 17 inches long.

These geckos have a heavy body, loose skin, and a small, stumpy tail. Their weight range is between 250 and 500 grams.

R. leachianus geckos come in a variety of colors, including mottled green, gray, and brown, with highlights of white, orange, and/or pink. They're variable in color, which is pretty cool.

In terms of overall bulk, R. leachianus geckos have a powerful build, large heads, and short tails. This gives them a more substantial appearance than other gecko species.

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R. leachianus is found in all of the southern and eastern portions of the main island of New Caledonia, as well as on several of the smaller islands in the group.

Topographical and ecological differences observed at each locality may have contributed to the phenotypical and morphological differences seen in R. leachianus.

The insular locality of Duu Ana is thought to no longer have an extant population of R. Leachianus.

R. leachianus is found in all of the southern and eastern portions of the main island of New Caledonia, as well as on several of the smaller islands in the group.

Topographical and ecological differences observed at each locality may have contributed to the phenotypical and morphological differences seen in R. leachianus.

The insular locality of Duu Ana is thought to no longer have an extant population of R. Leachianus.

Mt. Koghis (Grande Terre) is home to a unique form of Rhacodactylus leachianus, known for their massive bodies and short, thick tails.

One of the most distinctive features of the Mt. Koghis leachianus is their unique head structure.

Two distinct forms exist: the light form and a dark (melanistic) form.

The Seipp line is the most commonly encountered form on Mt. Koghis in the wild.

Rhacodactylus leachianus geckos are primarily nocturnal, hiding in tree hollows during the day. They are arboreal, which means they spend most of their time in trees.

Their diet consists of a variety of food sources, including insects, spiders, small vertebrates, fruit, nectar, and sap. The most common component of their diet is the fruit from Cassine curtipendula.

These geckos have a unique ability to climb vertically up glass surfaces, thanks to their adhesive pads called lamellae. These pads are made up of tiny hairs that increase friction force when applied to surfaces.

R. leachianus also possess large claws that aid in climbing. They can drop their tail, a self-amputation process known as autotomy, to escape predators.

Unlike some other geckos, R. leachianus are capable of tail regeneration through a process known as epimorphosis. This means they can regrow their tail if it's lost.

Male and female R. leachianus display differentiating morphological characteristics, known as sexual dimorphism. Males have a hemipenal bulge at the base of the tail, while females do not.

R. leachianus is observed to have temperature-dependent sex determination. This means that the sex of the offspring depends on the incubation temperature of the eggs.

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Populations of the Rhacodactylus leachianus have likely been reduced by habitat destruction and degradation, which is still a threat to the species.

The species faces predation by introduced species such as cats and various rodents, and is also poached. It can be electrocuted when it travels along power lines.

This species is protected and it lives in several nature reserves.

Populations of the species R. leachianus have likely been reduced by habitat destruction and degradation.

Habitat destruction and degradation are still major threats to the species, which also faces predation by introduced species like cats and rodents.

The species is protected, but it's still vulnerable to being poached.

Electrocution is another risk when it travels along power lines, which is a surprising and sad consequence of human activity.

This species can be found living in several nature reserves, which is a positive sign for its conservation status.

Giant geckos have been in the US hobby for nearly as long as some related species, but they're not as popular as crested geckos.

In 1992, Philippe DeVosjoli, Alan Repashy, and Frank Fast traveled to New Caledonia and collected individuals that served as the founder stock for many of the geckos available in the US today.

Reptile shows are perhaps the best method for locating a leachie, as breeders often have tables at larger events like the National Reptile Breeders Expo in Daytona, Florida.

Giant geckos are still not a common sight in most pet stores, but they're more available now compared to previous years.

Online classified postings are a good option for those unable to attend a reptile expo in person, and it's possible to find a leachie through these listings.

Leachie geckos require a spacious enclosure that allows them to explore, hunt, and exercise naturally. A minimum recommended enclosure size for R. l. leachianus is 48”L x 24”W x 48”H / 120 x 60 x 120 cm, while R. l. henkeli requires a minimum of 36”L x 18”W x 36”H / 90 x 45 x 90 cm.

A large, heavy-bodied gecko like the R. leachianus needs substantial hides and climbing perches. Wooden nest boxes, driftwood, and cork rounds can provide ample hiding spots and climbing opportunities.

To maintain a healthy environment, it's essential to keep the enclosure clean and well-ventilated. Leachie geckos are messy eaters, and their feces can be challenging to clean up. A utilitarian cage design is recommended for ease of maintenance, and regular cleaning is essential to prevent health issues.

Here are some recommended enclosures for housing leachie geckos:

Leachie geckos require a large enclosure to allow them to explore, hunt, and exercise natural behaviors. The minimum recommended enclosure size for R. l. leachianus is 48”L x 24”W x 48”H / 120 x 60 x 120 cm or equivalent.

They are arboreal, so they need a terrarium with plenty of climbing space. The minimum recommended enclosure size for R. l. henkeli is 36”L x 18”W x 36”H / 90 x 45 x 90 cm or equivalent.

A good enclosure for leachie geckos should have substantial hides as well as climbing perches. This can be achieved with wooden nest boxes, such as those designed for parrots, and large sections of heavy driftwood.

Leachie geckos require frequent cleaning due to their messy diet, which consists primarily of fruit and nectar-based foods. They will defecate throughout their vivarium, including on all four sides of the glass.

Here are some enclosure options that are suitable for leachie geckos:

If you're looking to create a more naturalistic enclosure, you can use durable plants like Sanseveria and other tough-leaved species that can withstand the weight of the geckos.

Leachie geckos do best in a high-humidity environment, with an average humidity of 60-80% as measured by a digital probe hygrometer with the probe placed in the middle of the enclosure.

Humidity levels that are consistently too high or low can cause health problems for your gecko. It's normal for humidity to be lower in the warm area and higher in the cool area.

It's also natural for humidity levels to rise at night and fall during the day. Levels as low as 50% during the day and 100% at night are fine.

To raise the humidity in your gecko's enclosure, use a pump-style pressure sprayer to wet down the enclosure every evening, and again in the morning if needed.

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When keeping leachie geckos, it's not necessary to use bedding, but it's super helpful for stabilizing humidity and providing a cushion if they fall from their perch.

A minimum of 3″ of moisture-retentive substrate is recommended, similar to the soil of a tropical forest floor.

You can choose from a variety of reliable options, including a DIY tropical mix made from 60% organic topsoil and 40% coconut fiber.

Here are some reliable substrate options:

For best results, add a generous layer of leaf litter on top of the substrate.

Daily feces and urates removal and regular substrate replacement are a must. Replace the substrate completely every 3-4 months.

Leachie geckos, also known as rhacodactylus leachianus geckos, are sensitive to heat stress and require access to areas of cooler temperatures to stay healthy.

Their ideal temperature range is between 72-78°F (22-26°C) for the ambient temperature, with a basking area temperature of 86-88°F (30-31°C). To achieve this, you can use a white incandescent heat lamp, such as the Exo Terra Daytime Heat Lamp, which should be placed about 12-18 inches above the basking area.

You'll want to create a temperature gradient in the enclosure, with the warmest temperatures at the top and the coolest temperatures at the bottom. This can be achieved by using thick vines, branches, and foliage at all levels.

A cluster of two 40w white incandescent bulbs should be enough to achieve the basking temperatures you need, but the exact results will vary based on your room temperature. If you notice the basking area is too warm, you can dial down the heat with a rheostat or switch to lower wattage bulbs.

To track the basking temperature, use a digital probe thermometer, with the probe zip-tied to the basking surface under the heat source.

Here's a quick reference guide to the temperature requirements for your leachie gecko:

Feeding your leachie gecko is a crucial part of being a responsible owner, and it's essential to understand their dietary needs.

Leachie geckos are omnivores, which means they need a balanced diet of both plant- and animal-based foods. In the wild, they eat mostly fruit and insects.

To ensure your leachie gecko gets the nutrition it needs, you should provide a varied diet. A good starting point is to use a rotation of at least 3 different kinds/flavors of Crested Gecko Diet (CGD) powder.

Here are some recommended CGD powders: Pangea, Repashy, Black Panther Zoological, Leapin' Leachie, Zoo Med, and Lugarti. And don't forget to mix it up with some feeder insects, such as crickets, dubia roaches, discoid roaches, and grasshoppers/locusts.

The frequency of feeding your leachie gecko depends on its age: juveniles (0-12 months) need CGD daily and insects every other day, while adults (>12 months) can go with CGD every other day and insects 1-2 times a week.

Providing a healthy and balanced diet will reward you with a healthier pet that always looks forward to mealtime.

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Before handling your leachie gecko, wait 2 weeks after bringing it home to allow it to settle in. This will help prevent additional stress.

It's essential to introduce yourself to your gecko by putting your hand in its enclosure every night for a few minutes, letting it get used to your scent and presence.

Start handling your gecko with 5-minute sessions every other day, gradually increasing the length of the sessions and escalating to daily. Consistency is key to successful taming.

Handling should be a positive experience, so stay close to the ground or a soft surface in case the gecko jumps. Injury is not a positive experience.

You should never grab the tail of your gecko, as it is detachable and can cause harm.

R. leachianus geckos are known to form pair bonds in the wild, but it's unclear if this is a real phenomenon for them. Reports from herpetoculturalists suggest that they may remain compatible for several years.

In captivity, some hobbyists keep pairs together until they display incompatibility, at which time they separate them permanently or reintroduce them to each other at a later date. Breeding behavior in captivity can be violent, involving biting and thrashing, but it's unclear if this is present in wild populations.

Adult females typically lay two eggs at a time, with up to 10 clutches per year, although older females may not lay clutches in a breeding season.

Breeding R. leachianus geckos can be a fascinating process, but it requires careful consideration and attention to detail. Adult males are identified by the presence of the hemipenile bulge and perianal pores.

Sexing juveniles can be more challenging, but a magnifying lens can help. Juveniles from offshore-island morphs should be at least 120 grams before breeding is attempted, while mainland geckos should be at least 180 grams.

Gravid females may refuse food just prior to laying, but they'll display ravenous appetites afterwards. Providing additional calcium during this time is essential.

Males will bite females around the neck area during mating, which can sometimes result in minor scarring. If significant damage is noticed, the pair should be separated.

Eggs are laid in clutches of two, with a typical annual yield of around three clutches per year. In some cases, females may lay up to 10 clutches per year.

Older females may not lay clutches in a breeding season, even when paired with a compatible male. However, they can still lay clutches over the course of their entire adult lifespan.

Incubating eggs is a crucial step in the breeding process for R. leachianus geckos.

You'll need to place the eggs in smaller plastic enclosures designed for baby reptiles, amphibians, and invertebrates.

Commercial hatching media is available, but the author prefers to rotate it with standard perlite, which can be found at most home and garden stores.

The media should be moist but not soaking wet, so be sure to check it daily to prevent it from drying out.

Standard recommended incubation temperatures range from 72 to 84 degrees Fahrenheit.

Incubation time can average from 45 to 150 days, depending on the temperature, but the author's incubation containers have an average incubation time of around 90 days.

The eggs can be placed in commercial plastic trays designed for reptile eggs, which are then placed in deli cups partially filled with water.

Rhacodactylus leachianus geckos can live a long time, with estimates ranging from over 30 to up to 50 years.

Their large size and cooler environment of origin likely contribute to their long lifespan.

Given their size, a long lifespan is not uncommon for these geckos.

A well-cared-for R. leachianus can thrive for many years with proper housing, diet, and care.

Their longevity makes them a rewarding pet for experienced reptile owners.

With the right environment, a R. leachianus can live a happy and healthy life.

It's essential to research and understand their specific needs to ensure they receive the best care possible.