The Red-Eyed Crocodile Skink ( Tribolonotus gracilis) is a captivating reptile species originating from the South East Asia, specifically New Guinea and Indonesia. These skinks inhabit leaf-littered forest floors and mossy tree crevices, often found near water sources within vegetation. Their unique appearance and relatively small size have made them increasingly popular among reptile enthusiasts, both experienced and novice. The name "Crocodile Skink" refers to their spiny appearance, much like a miniature crocodile, Red eye skinks also have an orange-red ring around their eyes. They are similar to the Fire skink or Pink tongue skink.
Natural Habitat and Behavior
Red-eyed crocodile skinks are native to the tropical forests of New Guinea and Indonesia. They have even adapted to living on coconut plantations because of deforestation. In their natural habitat, they are commonly found under forest debris, usually near a body of water. These skinks are crepuscular, meaning they are most active during dawn and dusk, when they would be feeding on a variety of insects. They are also semi-fossorial, spending a significant amount of time digging and hiding. Crocodile skinks can be an elusive pet, due to their natural crepuscular lifestyle and camouflage against earthy substrates.
Physical Characteristics
Red-eyed crocodile skinks typically measure around 6-8 inches (16-20 cm) in length. Their coloring is generally dark brown, gray, or black, with distinctive orange rings around their brown-black eyes. They have a large triangular head with a small snout and large eyes, as well as a stout body. Their most prominent feature is the rows of backward-curving spikes down their back and tubercles on their sides, giving them a dragon-like appearance.
Enclosure Requirements
Tank Size
For an adult skink, a tank size of 90 x 45 x 45cm is recommended to ensure they have a good opportunity for roaming and exercise, some great examples of these terrariums can be found in the Exo Terra range. A 15 or 20 gallon tank will suffice for one or two skinks. Go with at least a 24″ long tank to provide enough space for your Croc Skinks to roam. Exo terra style terrariums are a great choice as well, as they provide easy access with front opening doors.
Substrate and Humidity
This species requires a high humidity of between 70-90% which can be reached with good substrate choices like soil and mosses, large water sources, general misting and even the addition of foggers, which make a visually appealing habitat. Red-eyed crocodile skinks are very sensitive to dehydration. Keep humidity levels around 70-80% during the day, and higher (80-100%) at night. Ambient humidity should be tracked via digital probe hygrometer with the probe placed in the middle of the setup.
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Substrate is an important part of a red-eyed crocodile skink terrarium. It helps maintain humidity and gives them something to dig around in, decreasing overall stress. It’s best to use a moisture-retentive substrate that is similar to the soil in a crocodile skink’s natural habitat. Some reliable options include:
- DIY tropical mix: 60% organic topsoil, 40% coconut fiber
- Zoo Med Reptisoil
- Zoo Med Eco Earth
- Exo Terra Plantation Soil
- The Bio Dude Terra Fauna bioactive kit
Only 2-4 inches should be needed, unless you are planting live plants directly into the substrate. Then add a generous layer of leaf litter on top. This substrate should be kept damp, but not sopping wet.
To raise the humidity in your enclosure, you can use a pressure sprayer like the Exo Terra Mister to mist the habitat every evening and morning, as well as possibly in the middle of the day. Alternatively you can install a Mistking automatic misting system. The enclosure should be well ventilated enough to dry out a bit between mistings. It’s good practice to use a reptile humidifier/fogger at night to help maintain high nightly humidity levels. Make sure to use reverse-osmosis or distilled water, and thoroughly clean out and sanitize the humidifier with veterinary-grade disinfectant like Rescue or F10SC weekly to prevent illness.
Water Source
A portion of the tank should also incorporate a large water source such as a pool, waterfall or built-in stream, assisting in humidity and encouraging natural aquatic behaviours. A medium to large water dish is also a necessity. Red Eyed Croc skinks are very fond of spending time in the water, so make sure to choose a dish or bowl that they can easily access. Always make sure it’s shallow enough that the lizards cannot get stuck inside and drown. I usually bury the dish partially so that they can get inside easily, and I leave a few small river stones in the water to provide a sort of stairway back out of the dish should the skinks choose to swim (And they will!) Another bonus is that a large, shallow dish will also aid in keeping those mid to high humidity levels we are aiming for. Note: Always use spring water or tap water that has been treated to be reptile safe. Although your skink will likely get drinking water from routine mistings, it’s best to always keep a bowl of clean water available.
Heating and Lighting
To provide an essential basking spot a bulb or ceramic should be used alongside the relevant thermostat. The hottest area in the tank, the temperature under the basking bulb should remain around 30-32C during the day. During the night, a natural nighttime drop can be achieved of 15C without heating although this should be tested and never assumed. Hides should be available on both the warm side and cool side as your skink is most likely to bask out of sight. The warm hide should be placed directly under the heat lamp, with the lamp placed on the extreme right or left of the setup.
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Red Eyed Crocodile skinks thrive in temperatures ranging from about 75-80 degrees. I typically keep ours right around 78 degrees and they thrive under those conditions. Some keepers may opt to use a small heat pad under their terrarium. If you go this route, you absolutely must use a thermostat to control the temperature. Otherwise, your terrarium could be subject to unforeseen temperature spikes which can harm your skink.
As well as heating, these skinks will also require UVB light, which is provided in a tube-like an Arcadia T5 6% which would be adequate as long the bulb is 40-45cm away. Much lower and Arcadia's shade dweller may be more suited. Lights should be left on for 12 hours/day. Technically red-eyed crocodile skinks can survive without UVB lighting as long as they get plenty of supplemented vitamin D3. However, you are still going to get the best results from using UVB lighting rather than relying on supplements.
To provide appropriate UVB to a red-eyed crocodile skink in an 18” tall enclosure, you will need one of the following:
- Arcadia T5 SO ShadeDweller kit - 8-10″ / 20-25cm
- Zoo Med T5 HO Reptisun 5.0 + VE T5 HO Fixture - 11-14″ / 28-35cm
- Arcadia ProT5 Kit with Forest 6% bulb - 11-14″ / 28-35cm
The recommended distances listed above are to be measured from the skink’s back to the UVB lamp. The bulb itself should be roughly 1/2 of the enclosure’s length, no more than 2/3. UVB bulbs must be replaced every 12 months in order to remain effective.
Hides and Enrichment
Red Eyed Crocodile Skinks are pretty shy creatures, so they spend a lot of their time hidden underneath cover. I always provide a few different options, especially if I’m keeping multiple lizards in a single enclosure. Cork bark, pieces of wood, or dedicated plastic hide boxes are all great choices. Make sure that whatever you use, there’s no way that the hide can shift and crush whatever is underneath. These guys will dig out a little hidey hole underneath and sometimes this can cause shifting.
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Decorations play a vital role in your skink’s enclosure as environmental enrichment. Enrichment items encourage exercise, stimulate your pet’s natural instincts, and help promote overall wellbeing. Many people will add plants, vines, etc, whether live or artificial. This is optional and purely up to you, but I personally prefer to add some foliage to give my terrariums a naturalistic look.
Diet and Feeding
Being insectivores, the Crocodile Skink will feed on a variety of live prey items such as crickets, cockroaches, locust, earthworms, small snails and calci worms - which should be dusted with relevant calcium and multivitamin supplements. Juvenile crocodile skinks should be fed daily, and full-grown adults should be fed every other day. Offer as many insects as the lizard is capable of eating in a 5-minute period, with each feeder being around half the size of than the animal’s head.
Best feeder insects for red-eyed crocodile skinks: crickets, dubia roaches, discoid roaches, mealworms, superworms, hornworms, silkworms, black soldier fly larvae, earthworms, canned snails
The key to providing a healthy, balanced diet for your pet is VARIETY. Provide as varied of a diet as you possibly can, and you will be rewarded with a healthier pet that always looks forward to mealtime.
Feeder insects need to be “dusted” with a light coating of calcium powder before every feeding to balance their calcium-phosphorus ratio, and adding a multivitamin to the routine helps prevent deficiencies from developing. There are many options, but Repashy CalciumPlus LoD is a solid all-in-one supplement for getting started. For best results, use as directed by the label.
Social Behavior and Handling
Red-eyed crocodile skinks are very shy and make better display animals than a pet you can handle or even watch all the time. For the most part, Red Eyed Croc skinks will fare best when left alone. I observe my skinks in the mornings and evenings when they are beginning to get active (feeding time!) and I keep handling to a minimum. Picking up your skink occasionally for a health check / quick examination is not going to hurt it, but repetitive handling can stress out your lizard and lead to health issues. If you want to interact with your pet crocodile skink, you can build trust by offering insects or treats via soft-tipped feeding tongs.
Maintenance
Feces and urates should be removed daily, and contaminated substrate should be scooped out and replaced. The only thing I’ll really do on a daily basis is a misting/spray down in the mornings and evenings to maintain the tropical environment in the enclosure. I will also do a water check to make sure there is always fresh water available. Other than spraying, water checks and feeding I try not to mess with them. These guys prefer being left alone and they will appreciate you for it!
Sexing Red-Eyed Crocodile Skinks
Red Eyed Croc skinks are pretty easy to sex. Physically, males are typically larger and have much broader heads. Males will have little white pads at the base of their middle two toes, while females will not.
Purchasing Red-Eyed Crocodile Skinks
Many importers and resellers carry Red Eyed Crocodile skinks for sale. You can find them for sale on the internet or at local reptile shows. Whether you get them from us or somebody else, make sure you do your research and set up your enclosure prior to bringing your lizard home!