Cave Geckos

by **Admin** on Thu Mar 12 2009, 21:21

Chinese Cave Gecko – Goniruosuarus hainanensis

A less common eyelash gecko found in the pet trade, these lizards originate from Hainan Island, off the coast of China. Many found in petshops are wild caught and in poor condition, though captive breeding of this species is becoming more wide spread.

Little is known about Goniurosaurus’ natural habitats, and many have become protected by Chinese law and many of these species are very similar in appearance, making identification for novices quite difficult.

I do not recommend G. hainanensis as a beginner’s reptile as due to their specific environmental needs they can be slightly more difficult to maintain compared to some other lizard species. I have also found them less tolerant of handling, being a more nervous species they are more prone to stress.

Some other cave gecko species have similar care requirements to G. hainanensis, but it's still important to research individual species care.

Appearance

G. hainanensis display many features found in other eyelash geckos: a triangular-shaped head; narrow neck; thin body; four limbs each ending with five clawed digits; and a soft, fine tail for storing fat during harsh times.

In my opinion the most stunning and noticeable feature of these geckos is their startling red eyes. They have black vertical pupils which expand in the dark (when they are most active).

Hatchlings come out of the egg at around 2-3in long, and as adults they usually reach 7in head to tail. Adults have a black/dark purple or grey body colour with dark spots, broken up by 2 white, yellow or orange bands on the back, one at the base of the tail and a v-shaped band on the neck. The neck band continues round the side of the head, past the ear to the back of the eye and/or corner of the mouth. Babies resemble the parents but slightly darker and with fewer spots, which appear with age.

I’ve found these geckos change colour at night; their dark bodies becoming paler with the exception of a dark outline around their yellow bands, which makes their spots stand out more. Their skin is very soft, and the back, head and top of the legs are covered with small nodules much like that of leopard geckos.

The tail is banded white and black (though I have seen some of my hatchlings with a faint yellow/green tinge to the whiter bands near the base of the tail but not in adults as yet) and is almost the same length as the body. The tail can be ejected at the base if the gecko is stressed or handled roughly, though will grow back but with an irregular pattern and possible different shape. This is most likely a defence strategy as the tail may continue to move after it has been dropped which may attract potential predators and let the gecko escape in the wild.

The cave geckos have claws, and are excellent climbers and diggers.

G. hainanensis and G. lichtenfelderi are both very similar in appearance, with more minute differences than major ones. The main way to tell them apart is by the length of the neck band – G. lichtenfelderi the band does not extend as far as in hainanensis, barely passing the ear. Judging by comparison photos the bands appear thinner on lichtenfelderi than its cousin, but I would not guarantee this as a precise method of identifying species.

Another common species seen in collections is G. luii. This cave gecko is easier to tell apart from hainanensis by an extra yellow band on the body, a more slender cat-like body and nose, duller eye colour, overall larger size and occasionally a more spotty coloration.

Environmental conditions

Although they have many similar physical characteristics as leopard geckos (so much so that they are sometimes known as Chinese Leopard Geckos), there are some major differences in G. hainanensis care.

First of all they require far lower temperatures than many other gecko species – during the day I have my vivariums at 28C/82F (hot end) to 24C/75F (cool end) and at night their temperatures drop to 21C/69F. Prolonged exposure to temperatures above 30C/86F or below 20C/68F is fatal for these lizards. As with most other reptiles it is important to provide caves with a range of temperatures ranging from the higher to the cooler (called a thermal gradient) throughout the enclosure so the geckos can choose what temperature they prefer. It is important to offer them hides at as many gradients as possible, so they feel secure at their desired temperature and also being a very shy and nocturnal species, they would become very stressed if not given the opportunity to hide.

They also require far higher humidity levels than leopard geckos – I aim to keep my enclosures between 60-80% humidity at all times. I always offer a wet box – a hide with constantly damp substrate. I have heard from other breeders that if the geckos are exposed to the dangerous temperatures mentioned above, there is a higher chance of survival if the gecko has access to damp hides and can remain well hydrated. I personally would not take this risk as the hides may dry out during hotter spells and do not recommend exposing the geckos to these temperatures to find out.

I have yet to see any of my caves drinking water from a dish, but often see them licking water droplets after being sprayed, so maintaining the humidity is vital to these geckos’ survival. A dish of fresh water should always be present in the enclosure even if you never see the gecko drink from it. If nothing else, this will help to maintain the humidity.

Shedding problems may also arise from too dry a viv, where skin may remain on the gecko and if not removed may constrict digits or limbs to the point where toes or legs may drop off. Unlike their tails, limbs or toes do not regenerate and lose of limbs may lead to infection and other problems.

Housing

Being a small lizard, a trio of adult caves can live comfortably in a 2ft x 2ft x 2ft vivarium. Choice of enclosure is down to personal preference, but a few things to keep in mind are:
• High humidity needs to be maintained, and some non-varnished woods will absorb the water, lowering humidity and attracting mites and fungus.
• Other plastic or glass vivariums may hold the humidity too well so will need extra ventilation.
• Wooden or other well-insulated materials may result in overheating so temperatures will need to be monitored, preferably having heating elements on suitable thermostats.
• The enclosure needs to be well ventilated for these humid-loving geckos to avoid fungus build up, mites, and other moisture-related issues.
• Glass may not hold temperatures well in poorly heated rooms.

I house my adults seperately in glass terrariums with a heat strip under one half of the viv. I find these vivariums maintain humidity very well, offer excellent ventilation and allow the range of temperatures the geckos need using the heat strip in a room kept at 20-21C/68-69F. The backgrounds give them opportunity to climb, and a few inches of coco fibre allows them to dig.

Being nocturnal, I have found they make the most of their space at night, when they are found everywhere in the vivarium including hanging upside down on the mesh lid! They do not seem to benefit from any light exposure, other than natural room lighting to give them a proper photoperiod (day and night cycle), as well as many bulbs giving off too much heat for these geckos.

Choice of substrate is always a debate amongst reptile owners and the same arguments will arise when housing cave geckos.

I do not recommend sand for a number of reasons:
• When hunting, the geckos may ingest it, which can clog up their insides – called impaction. The result of impaction is usually death, as the signs are difficult to spot.
• Being a small gecko species, dust from the sand can become trapped under scales leading to infections, and/or breathed in, causing respiratory problems.
• Sand does not hold humidity well for these humid-loving geckos, and risks drying them out too much.

I also do not recommend bark or beech chips as the chips are usually quite large for these geckos to dig in, and any free-roaming crickets can easily hide in it leaving the geckos with less food.

The safest substrates to use are newspaper or paper towels due to cheap and abundant availability, no impaction possibilities and easy of cleaning, though is not very aesthetically pleasing. For hatchlings and juveniles I use paper towels for the reasons mentioned above, and I keep adults on Eco Earth/coco fibre as it is believed to have less impaction risks than sand or other fine substrates, and has a more natural appearance. Owners should be aware that impaction is always a risk when using any loose substrate.

Diet

Cave geckos are insectivorous – i.e. they eat insects. Crickets are the main insect I offer, as they are most readily available in a variety of sizes, are easily dusted with supplements and offer the caves hunting opportunities. I have offered waxworms, mealworms, buffalo worms and hoppers with no success though other breeders I have spoken to have had more luck feeding other insects. Waxworms are high in fat and if eaten should only be offered occasionally, as other lizards are known to become addicted to them. I have found my caves seem rather fussy about the size of their food items, keeping to smaller crickets rather than larger; food items should be no larger than the gap between the gecko’s eyes to ensure proper digestion and less risk of choking.

As these geckos do not emerge during daylight hours they do not receive UVB from natural light as other reptiles do, so this must be supplemented into their diet along with other vitamins and minerals that ensure the caves receive the proper diet. I dust crickets with Nutrobal, a general nutrient supplement that I have found to be very effective. With young or gravid (pregnant) lizards I offer extra calcium once a week to ensure proper bone and egg growth and with all my geckos I leave a small dish of calcium powder in the vivarium so they may take any extra that they require. This is not a guaranteed way to get calcium into reptiles so dusting the food is vital to ensure they are receiving their supplements. It is important to use recommended amounts of any supplements – over dosing can occur as easily as under dosing.

Due to their digging habits I wonder if in the wild they forage for food, but have yet been unable to determine this in my captive environments.

Sexing and breeding

G. hainanensis are sexable at around 6-8 months of age when males begin developing hemipenal bulges at the base of the tail, which females lack. Juveniles can be housed in groups until this age when they should be separated to avoid early breeding and male territorial disputes. Males can become aggressive to each other, and so there should be no more than one adult male per enclosure. Females seem to co-exist well with each other and with males as long as there is adequate room. These geckos seem to do well in groups of 1 male to 2 or 3 females (often written as 1:2 or 1:3).

A general rule is that they become sexually mature at around 12 months of age, though it is not unknown for females to breed earlier than this. I do not recommend allowing females younger than 18 months to breed as problems can arise: the gecko is still growing when below a year old, and if gravid the strain of trying to carry eggs may kill her. She will be using her own body to nourish the eggs which will deprive her of the valuable nutrients she needs to continue growing – the most noticeable result will be weak bones, or weak egg shells due to lack of calcium. Also at young ages the fully developed eggs may be too large for the female to lay, leading to her becoming egg bound (when the eggs become trapped inside the female, and kill her).

It is important to ensure the female(s) receive extra calcium in their diet to help them develop healthy eggs without endangering their health. Some breeders will put their cave geckos through a cool period over winter – known as brumation – reducing temperatures by a few degrees and shortening daylight hours over a couple of months. This allows the female to rest before breeding and prepares both sexes for the breeding season.

A few weeks after a successful mating the female will begin digging round her enclosure, looking for a suitable place to lay her eggs. She will begin to fatten up and if held carefully the eggs can be seen through the skin on the underside of her belly as two large white ovals. I always have a wet box in the viv anyway but if you do not, it is important to put one in now. I add a few inches of damp vermiculite as a substrate in these hides and check it on a daily basis for any laid eggs.

Caves lay two eggs at a time, over a matter of months. A healthy female may produce 4/5 clutches of two eggs a year, or more. Some breeders keep their males and females separate allowing them a limited time to breed then to be separated again. This is convenient for large breeding colonies where the males have to be rotated and where strict breeding records need to be kept.

Once the eggs have been laid they should be removed from the nest box to avoid them being dug up. It is vital that the eggs are not turned as this can kill any developing embryos. I have successfully hatched eggs that were half buried in damp vermiculite in a tub placed at the cool end of the vivarium and also eggs which have been removed after laying and placed into an incubator.

The tubs should be damp and well ventilated, but condensation shouldn’t be allowed to drop onto the eggs – water on the shells will suffocate the embryos. It is important to keep the eggs humid, however too much water will cause pressure in the egg and kill the baby, or low ventilation will cause fungus to grow. The length of time from being laid to hatching depends on what temperature they are incubated at – the lower the temperature the longer the incubation time. At 20-24C (my cool end temps in the viv, night/day) my eggs hatched at between 105-120 days, at a steady 24-25C, the eggs have hatched at around 80 days.

It is believed many of the Goniurosaurus sp. are temperature sex dependent which means that certain genders of geckos will be produced when the eggs are incubated at particular temperatures. According to other breeders I’ve spoken to males seem to be produced at lower and higher end temperatures, females at the mid-range. This is also seen in leopard geckos and some other reptiles though different species seem to have different genders for different ranges.

When the eggs begin to pip, the babies should be left alone until they have left the egg entirely. They may remain half out of the egg for hours or ever days as their lungs adapt to the air they are breathing. The babies will shed within a few hours or a day after hatching, and will not feed for 5-7 days as they absorb what remains of their yolk from the egg. When they are ready to begin feeding, I start them on 1st instar crickets until I am sure they can manage bigger items. The young should be housed in a similar fashion to the adults.