New Caledonian giant gecko
Rhacodactylus leachianus
Photo: Rhacodactylus leachianus 33603748 · Lennart Hudel · CC BY 4.0 · Changes and credits
These guides provide general husbandry information and do not replace veterinary assessment. If your animal shows symptoms or its condition worsens, contact a veterinarian experienced with exotic animals.
- Warm zone
- Basking surface: 30–31 °C
- Cool zone
- Cool air: 22–26 °C
These notices cover the cited provisions, not every possible national or local rule. Check additional requirements with the competent authority.
Description
Rhacodactylus leachianus is the largest living gecko and inhabits New Caledonian forests. It has a heavy body, loose folds of soft skin and mottled colours that blend with bark. It spends much of its time on trees and in cavities; it is nocturnal, territorial and capable of conspicuous calls.
Behaviour
Observe the individual’s behaviour and limit handling.
Housing together
House animals individually with their own water, food and retreats. Before a breeding introduction, prepare separate accommodation and watch the encounter. Stop persistent pursuit or exclusion from retreats and food; do not leave individuals together when they cannot withdraw from the partner.
Enclosure and climate
For Rhacodactylus leachianus secure thick branches and cork tubes that support the adult body without rotating. Connect cavities to elevated food and cool-area retreats with foliage cover along routes. Hide openings must allow the adult animal to enter, turn and leave without becoming wedged.
Night: 19–22 °C.
Setup
Secure cork tubes against rolling and choose openings suitable for the adult size of the identified locality.
Making height usable
Secure horizontal, sloping and vertical branches to the structure, using diameters that offer grip and supports suitable for adult weight. Connect them from the exposed lighting branch to the cool area, distributing supports across levels. Place hide entrances beside branches; add foliage along routes without blocking dishes, doors or vents.
Testing and access
Connect specified heat sources to compatible thermostats and guard against contact. Secure probes according to device instructions; measure air at resting sites and heated surfaces separately with independent instruments. In housing with water, also check water temperature and quality: one zone’s thermostat does not control the others.
With the complete enclosure running, record day and night readings and compare them with the sheet. Test doors, cable openings and cleaning access, keeping vents clear. Change one variable at a time and recheck after each adjustment.
Lighting and UVB
Ferguson zone not assigned with sufficient precision to this taxon.
At the exposed position aim for approximately UVI 2–3, measured at the back or head. The animal must choose its exposure and reach UVI 0 retreats. This local target differs from the Ferguson ecological band and should not be maintained everywhere throughout the day.
UVB is recommended at an intensity appropriate to the species, with the option to withdraw from the light. Evidence of its necessity varies between animals: assess exposure alongside diet and species identification.
UVA is recommended as part of daytime lighting, including when UVB has not been shown to be indispensable. Check the UVB source’s spectrum, as it may already emit UVA: a second lamp is not automatically necessary.
Linear UVB tube with reflector. Indicative UVB percentage stated on the lamp: 2–7%; final selection depends on UVI achieved at the actual distance.
For maintenance, a cycle of approximately 12 hours of light and 12 hours of darkness can serve as an initial reference. Use a timer to switch lights off at night, and keep retreats available so the animal can withdraw from light during the day. Adapt day length to species and origin, following the specific guidance for seasonal care and breeding.
Light in the animal’s daily life
The Ferguson zone is unverified for this taxon; the proposed peak is a separate practical recommendation. Illuminate the gecko’s whole back and leave a dark cavity as a retreat.
An example layout in the enclosure
To make the layout concrete, take housing measuring 90 × 45 × 90 cm, using the first dimensional configuration in the sheet. This is a mounting example: retain the conditions and any alternatives attached to the stated minimum.
In a wooden enclosure with internal lighting, imagine the tube 85 cm above the floor and the back or head at 45 cm. The geometric distance is therefore 40 cm. The branch or platform lies below animal height, according to body size. Place lighting over one side, with a route to fully screened retreats.
In a glass enclosure with a mesh roof, retain the same animal height and imagine the tube 5 cm above the mesh: distance becomes 50 cm. Mesh attenuates UV variably; ordinary glass roofs block UVB. Increasing the percentage alone is insufficient: measure beneath the mesh and adjust height, output or layout as needed.
These distances describe the example, not a safe clearance for every lamp. Select the source and adjust mounting until approximately UVI 2–3 is measured at animal height in the exposed position. Also respect the minimum clearance specified for the model used. Recheck with furnishings, guards and mesh installed, including the highest reachable points and animal growth.
Choosing and checking lighting
First define the patch that should illuminate the whole body and the route to a screened retreat. For a broad patch, select a linear tube with reflector; consider a compact only if its useful patch covers the body and leaves an accessible gradient. Check model, output, reflector and mounting distance, then compare measured UVI with the species target. Label UVB percentage alone cannot determine distance and intensity.
The decisive check uses a UVI metre facing the source at animal height. Check the centre and edges of the exposed patch, the highest supports and retreats, which must allow withdrawal from UV. Repeat after moving equipment, changing lamps and plant growth. Without a metre, use the manufacturer’s instructions and measurements for the exact configuration, including safety clearances.
When UVB or UVA are absent
When keeping without UVB, D3 must be supplied through a complete diet or species-appropriate supplementation. Calcium alone does not replace D3. Check existing amounts in prepared diets and multivitamins before combining products; dosage also depends on diet and cannot be derived from lighting hours.
UVA contributes to environmental perception and behaviour and cannot be replaced by vitamins or calcium. A reptile UVB source normally also emits UVA: check its declared spectrum. If the existing lighting lacks it, complete the installation with a suitable source; an ordinary white LED does not guarantee UVA and a UVA-only lamp does not provide UVB.
Humidity and ventilation
Maintain average humidity at 60–80%, with higher values at night and adequate air exchange. Place the hygrometer beside resting branches, outside the direct water spray, and compare readings with the cool area. Record the trend after water input; if readings stay outside the specified range, check foliage blocking vents and surfaces that remain wet before adjusting misting.
Feeding
Rhacodactylus leachianus: choose a complete New Caledonian gecko formulation and cups that allow intake to be measured. Large size does not require routine rodents.
Recommended foods
The tiers describe dietary use: rotate foods within each tier rather than treating them as an absolute nutritional score.
| Food | Dietary role | Benefits and limits | Preparation |
|---|---|---|---|
| Complete fruit-eating gecko diet (CGD) | Main choices | A formulation labelled complete provides protein, calcium and vitamins in defined proportions; fruit purée and supplementary nectar are not equivalents. | Measure powder and water separately in the package ratio, then mix to the specified consistency. Place a portion in a clean, reachable cup. Record preparation time and discard leftovers within the stated time, sooner if appearance or smell changes. |
| Crickets and locusts | For rotation | Supply protein and encourage hunting; calcium is low relative to phosphorus, so preparation and supplementation are needed. | Use captive-bred insects and gut-load them as described below. Select suitably sized feeders, place the meal’s batch in a clean container and apply a thin calcium coating immediately before offering them. |
| Feeder roaches | For rotation | These feeders provide a useful second protein source for rotation, but do not constitute a complete diet or replace calcium supplementation. | Offer well-fed soft nymphs sized to the mouth; avoid excessively hard adults. |
| Ripe fruit | Occasional | Rich in water and sugar and not a complete food; offer a small taste replacing part of the meal. | Wash and remove stones and large seeds; no syrup-preserved fruit, honey or added sugar. |
| Wild insects, fireflies and contaminated prey | Avoid / not a staple | May carry pesticides, parasites or toxins; a healthy appearance does not establish safety. | Use traceable feeder cultures; do not collect insects beside roads or treated gardens. |
Comparable nutritional values
Protein, fat, calcium and phosphorus are percentages of dry matter, excluding water; dry matter itself is a percentage of fresh weight. These are reference analytical values compiled in a clinical table, not guaranteed contents of your batch or a universal ranking. Age, rearing, feeding and supplementation change composition. Do not compare them directly with fresh-food percentages or already diluted prepared diets. Comparable numbers are not provided for other foods.
| Insect | Dry matter | Crude protein | Crude fat | Calcium / phosphorus | Ca:P |
|---|---|---|---|---|---|
| Adult house cricketAcheta domestica | 32% of fresh weight | 62.6% DM | 20.4% DM | 0.3 / 1% DM | 0.3:1 |
| Migratory locustLocusta migratoria | 31% of fresh weight | 67.5% DM | 14% DM | 0.1 / 0.7% DM | 0.14:1 |
DM = dry matter. Ca:P describes calcium relative to phosphorus before supplementation: a protein-rich feeder may still be calcium-poor. Offered portions remain those for this species and life stage.
Meals by age and size
| Stage and size | Frequency | Amount per meal |
|---|---|---|
| Hatchlings and growing juveniles | Prepared diet each evening; small insects 1–2 times weekly | Spread a thin layer of diet in the cup so lick marks are visible. Measure the amount prepared and left; next time make slightly more than actual consumption rather than a large reserve. Insects replace part of the prepared diet. |
| Subadults, with slowing growth | Prepared diet every other day; insects 1–2 times weekly | Spread a thin layer of diet in the cup so lick marks are visible. Measure the amount prepared and left; next time make slightly more than actual consumption rather than a large reserve. Insects replace part of the prepared diet. |
| Adults: near final size, growth has slowed | Prepared diet every other day; insects 1–2 times weekly | Spread a thin layer of diet in the cup so lick marks are visible. Measure the amount prepared and left; next time make slightly more than actual consumption rather than a large reserve. Insects replace part of the prepared diet. |
Adjusting portions
To assess the portion, compare the amount and type of food eaten with growth and body condition. Weekly weighing of juveniles and monthly weighing of adults helps follow the trend. Adjust the ration gradually when growth or reserves require it; reduce it if body condition indicates excess weight or leftovers remain. Investigate unexpected weight loss or abnormal swelling rather than addressing it only with more or less food.
Preparing and offering meals
Prepare insects during the 24–48 hours before feeding: keep them in their culture container with a complete feeder diet and safe hydration. Check access to food and water and remove spoiled leftovers. Then select feeders of the specified size and prepare only the batch to be offered. This step, called gut-loading, improves prey quality; bran or potato alone do not correct deficiencies.
At feeding time the prey should be easy to swallow. As an initial guide, choose insects no wider than the space between the eyes, then adapt size to the mouth and the animal’s response. Offering them individually or in an escape-resistant dish lets you see actual intake and remove leftovers.
Place stable cups near frequently used branches. Avoid routine hand-feeding: accessible cups allow independent feeding to be verified.
Trial amounts are a starting point for a healthy, active animal at correct temperatures: record intake and weight trend, then adjust the ration. Do not feed again merely because it continues striking at prey.
Calcium and vitamins
Do not add calcium or vitamins to an already complete diet unless prescribed. Separately offered insects need preparation and supplementation; do not layer insect-only supplementation doses onto an already fortified diet.
Choose one supplementation programme: plain calcium for ordinary meals and a species-appropriate multivitamin at its labelled feeding intervals. Record the product and its existing D3 and vitamin A; do not add a second dose to meals using a combined product. With measured UVB, agree the oral D3 provision; product concentrations are not interchangeable.
Daily care
First days
Keep retreats accessible and observe without opening them to look for the animal. Check climate readings from outside, offer scheduled food and record actual intake. Prepare the scales and container before weighing so the transfer stays brief; compare weight with earlier records rather than relying on appearance alone.
Cleaning
Keep animals and equipment away from kitchens and food areas, use tools dedicated to each enclosure and wash your hands with soap and running water after handling animals, food, tank water or furnishings. Quarantine new arrivals separately and agree the duration and checks with a veterinarian before introducing them to established animals.
Handling
Before a transfer, prepare an open container and an access route. Allow the animal to enter where possible; if support is necessary, support its body without gripping the tail and minimise time out of the enclosure. Stop repeated attempts to grasp it and allow withdrawal to a retreat.
Checks
Record weight, appetite and behaviour; consult a veterinarian experienced with the species if changes persist. For laboured breathing or wounds, contact them promptly without waiting for symptoms to persist.
Breeding
Sex, maturity and readiness
Identify locality and line size: island and Grande Terre forms do not share one breeding weight. Wait for developed adults; males show pores and a hemipenal bulge. Pair compatibility is a separate requirement from maturity.
Start a record for each breeding animal with identity, origin, documented age and previous weights. Compare the weight trend with growth and body condition; delay introductions for animals still growing rapidly, losing weight or recently acquired. Use stated ages as guidance alongside these checks. If sex cannot be identified reliably, obtain assessment by qualified personnel before pairing.
Preparation and seasonal cycle
Prepare hollow shelters and dividers before pairing. Introduce under observation and retain only pairs tolerating one another without injury; do not repeatedly swap partners in a stable pair. A mild cool pause must remain appropriate to origin.
Before encounters, prepare and test offspring enclosures and have first foods available. Check records for regular adult feeding and good body condition, then verify access from exposed areas to retreats. If the species protocol includes seasonal changes, adjust settings gradually and record the response. Record night-time air, surface and egg temperatures separately, noting where each is measured. Keep water available throughout preparation.
Courtship and mating
Introduce only identified, compatible adults, with another enclosure ready. Observe from a distance and end the encounter if you observe persistent pursuit, injuries or an animal unable to move away from its partner; do not forcibly separate animals during copulation. Record the date, both identities and what you actually saw: courtship, contact or mating alone does not prove fertilisation.
Before laying and the nest
Females usually lay two eggs in protected sites. Offer a roomy moist nest inside or near a cavity that can be checked without dismantling shelters. Avoid disturbance while the female digs and closes the site.
Maintain a suitable laying site even without a male: females can produce unfertilised eggs. Persistent straining without laying, weakness or tissue protruding from the vent require prompt veterinary assessment. Do not wait for a predicted laying date if these signs appear. Do not squeeze the abdomen, pull eggs or give drugs to induce laying without veterinary direction.
Egg incubation
Keep eggs stationary on moist, ventilated medium, away from enclosure hot spots. Documented lines and seasonal regimes differ: no universal temperature-duration pair is assigned here. Record actual temperature and development without using a crested-gecko timetable.
Test the system before laying with an independent probe at egg height. Use clean, labelled containers, closed but allowing air exchange, with room for eggs and hatchlings. Keep eggs in their original orientation and do not detach eggs glued to their support. The substrate should retain moisture without free water on the shell; check condensation and water loss, adding water at the edge of the substrate rather than onto eggs. Record temperature and events daily without needless opening. The stated times are approximate: do not increase heat to meet a date.
First meals and juvenile care
Prepare sturdy individual juvenile enclosures with cork and proportionate branches. Once yolk is absorbed, offer complete fruit-gecko diet and appropriately sized insects; directly verify each youngster feeds. Keep identity and locality attached to every offspring record.
During the first weeks, monitor each youngster: a feeding group does not guarantee that every individual eats. Record intake, droppings and weight at regular intervals to follow growth and adapt housing and food size. Provide separate accommodation if competition prevents an individual from feeding or size differences become marked. Document repeated independent meals before transfer to another keeper.
Female recovery
After reproduction provide water and the usual balanced diet, initially in manageable portions; monitor weight, activity and return of appetite. Keep supplements and lighting consistent with the feeding guide. Avoid further introductions until the previous condition has recovered; later clutches may occur without another mating. Persistent straining, weakness or protruding tissue require veterinary attention, without squeezing the abdomen.
Equipment and example diary
Place the nest where it can be checked without dismantling the enclosure. Label containers with female identity and laying date and prepare the specified medium; for attached eggs, instead provide guards in place without detaching them. If using an incubator, install a thermostat and independent probe and test it before laying. Run offspring enclosures too and prepare scales and first food, reserving capacity for later clutches.
A consistent diary using actual dates helps follow reproduction in Rhacodactylus leachianus. Start with adult identity, weight and condition, then record observed encounters, laying or birth and development conditions. After emergence record the first meal actually accepted and each youngster’s growth while continuing to follow female recovery. Over time these records help identify your lineage’s pattern without turning approximate durations into deadlines.