Red-Eyed Crocodile Skink (Tribolonotus gracilis) Care Sheet
The Red-Eyed Crocodile Skink is a small, distinctive tropical skink native to Papua New Guinea. With heavily keeled armour-like scales, prominent dorsal ridges and characteristic orange-red colouration surrounding the eyes in mature animals, it has an unusually prehistoric appearance.
Despite their dramatic appearance, Red-Eyed Crocodile Skinks are shy, secretive animals. They spend considerable periods concealed beneath leaf litter, bark and other cover and are most active during periods of low light and darkness.
They are best regarded primarily as a display species rather than a reptile for frequent handling.
Successful husbandry depends particularly upon providing a cool-to-moderately warm, humid, heavily covered forest-floor environment with access to clean shallow water.
Quick Facts
Scientific name: Tribolonotus gracilis
Common name: Red-Eyed Crocodile Skink
Family: Scincidae
Origin: Papua New Guinea
Adult size: Approximately 16–20 cm (6–8 in) total length
Lifespan: Approximately 8–10+ years with appropriate care
Activity: Primarily crepuscular and nocturnal
Lifestyle: Terrestrial and semi-fossorial
Diet: Primarily insectivorous/invertebrate-feeding
Reproduction: Oviparous (egg-laying)
Temperament: Shy, secretive and easily stressed
Handling: Best kept primarily as a display species
Experience level: Intermediate
Natural Range & Habitat
Tribolonotus gracilis is native to Papua New Guinea.
The species inhabits humid tropical forest environments and is strongly associated with moist ground-level microhabitats.
They utilise:
- Leaf litter
- Fallen bark
- Logs
- Rocks
- Dense vegetation
- Soil cavities
- Other forest debris
They are frequently associated with areas close to water.
Red-Eyed Crocodile Skinks spend substantial periods concealed.
This is completely normal behaviour.
A skink that spends much of the day hidden should not automatically be considered unhealthy.
Their captive enclosure should reproduce the cool, humid, heavily covered conditions of a tropical forest floor rather than creating a hot, exposed basking environment.
Appearance
Red-Eyed Crocodile Skinks possess:
- A robust body
- Large head
- Strongly keeled scales
- Prominent dorsal ridges
- Relatively short limbs
- A heavily armoured appearance
Mature animals develop the distinctive orange to reddish colour surrounding the eyes from which the common name originates.
Juveniles do not initially display the same fully developed eye colouration seen in adults.
Adult Size
Adults commonly reach approximately:
16–20 cm (6–8 inches) total length
A substantial proportion of this consists of the tail.
Although physically small, they should not be maintained in excessively small accommodation.
Environmental complexity, cover and access to different microclimates are particularly important.
Enclosure
For a single adult, approximately:
60 × 45 × 45 cm
provides a useful minimum starting point.
Larger accommodation is encouraged where appropriate temperature and humidity can still be maintained.
The enclosure should contain:
- Deep substrate
- Extensive leaf litter
- Multiple secure hides
- Cork bark
- Plants
- Shaded areas
- Clean shallow water
- High humidity
- Good ventilation
The enclosure should feel heavily covered rather than open.
A well-planted naturalistic or bioactive enclosure can work particularly well.
Enclosure Security
The enclosure should be securely closed.
Check:
- Doors
- Ventilation openings
- Cable holes
- Lid edges
- Other potential escape points
Any aquatic feature should also be designed so that the animal can enter and leave easily.
Temperature
Red-Eyed Crocodile Skinks should not be maintained excessively hot.
A useful general daytime range is approximately:
22–26°C
A slightly warmer localised area of approximately:
26–28°C
can be provided.
Cooler portions of the enclosure should remain approximately:
21–24°C
Night temperatures can decrease to approximately:
20–22°C
for healthy established animals.
Prolonged temperatures around or above 30°C should be avoided.
This is a humid tropical forest-floor species, not a heat-loving basking lizard.
Heating
Whether supplementary heating is required depends upon ambient room temperature.
In a suitably heated reptile room, little additional heat may be necessary.
Where heating is required, a low-powered overhead heat source can be used to establish a gentle thermal gradient.
All heating equipment must be appropriately thermostatically controlled.
Any internally mounted heat source accessible to the animal must be securely guarded.
The animal must always be able to retreat into cooler, humid areas.
Lighting
Provide a clear day/night cycle.
Approximately:
12 hours light / 12 hours darkness
provides a useful general starting point, with seasonal variation possible.
The enclosure should become genuinely dark at night.
Avoid coloured nighttime bulbs.
UVB
Although Red-Eyed Crocodile Skinks are primarily crepuscular/nocturnal and spend considerable periods under cover, they still experience natural daylight and ultraviolet radiation.
Low-level UVB is recommended.
A useful exposed target is approximately:
UVI 1–2
with substantial areas of very low or negligible UV exposure.
Provide abundant:
- Shade
- Plants
- Leaf litter
- Cork
- Dark hides
The skink must always be able to completely withdraw from UVB exposure.
Actual UV intensity depends upon the lamp, reflector, mesh, installation distance and enclosure design, so output should ideally be checked using an appropriate UV meter.
Humidity
High humidity is important.
A useful general range is approximately:
70–90% relative humidity
with natural fluctuations.
Humidity will commonly increase:
- Following misting
- Overnight
- Within humid retreats
- Near the water area
High humidity should not mean stagnant air or permanently saturated substrate.
The enclosure should combine:
- High ambient humidity
- Moist lower substrate
- Leaf litter
- Good ventilation
- Clean water
- Areas where surface moisture can partially dry
A digital hygrometer should be used for monitoring.
Misting
Misting can help reproduce natural humidity cycles and provide drinking droplets.
Frequency depends upon:
- Enclosure ventilation
- Ambient room humidity
- Substrate
- Planting
- Water features
A useful pattern is:
Mist → humidity rises → surfaces partially dry → mist again
rather than keeping every surface permanently saturated.
The measured conditions inside the enclosure are more important than following an arbitrary number of misting sessions.
Water
Access to water is particularly important.
Red-Eyed Crocodile Skinks readily utilise shallow water.
Provide a large, shallow water area that the skink can enter and leave easily.
The water must not be so deep or difficult to exit that drowning becomes a risk.
Rocks, cork or branches can provide easy access and exit points.
Water should be:
- Checked daily
- Kept clean
- Replaced immediately when contaminated
A filtered aquatic section can be incorporated into larger naturalistic enclosures provided it is appropriately designed and maintained.
Substrate
The substrate should reproduce a moist tropical forest floor.
Suitable components include:
- Organic reptile-safe topsoil
- Coco fibre
- Coco husk
- Sphagnum moss
- Orchid bark
- Tropical bioactive substrate
- Leaf litter
A substrate depth of approximately:
8–15 cm
is beneficial.
The lower layers can remain moist while the upper surface varies between damp and partially dry.
Generous leaf litter should be provided.
Leaf litter is not merely decorative — these skinks naturally hide and forage beneath surface debris.
Avoid:
- Cedar
- Strongly aromatic wood products
- Very dry dusty substrates
- Permanently waterlogged substrate
Hides & Cover
Extensive cover is essential.
Provide multiple hiding locations using:
- Cork bark
- Flat bark
- Hollow cork
- Leaf litter
- Plants
- Moss
- Rock caves
- Half logs
- Other secure retreats
At least some retreats should remain humid.
Ideally, the animal should be able to move through much of the enclosure without feeling completely exposed.
Plants
Live plants can work extremely well.
They provide:
- Visual security
- Humidity retention
- Shade
- Natural cover
- Environmental complexity
Choose non-toxic plants capable of tolerating humid tropical conditions.
Planting should not completely eliminate airflow.
Environmental Enrichment
Red-Eyed Crocodile Skinks benefit from a structurally complex enclosure.
Suitable enrichment includes:
- Deep substrate
- Leaf litter
- Cork bark
- Plants
- Logs
- Moss
- Shallow water
- Different textures
- Multiple concealed routes
- Naturalistic feeding opportunities
Enrichment should encourage:
- Foraging
- Digging
- Exploration
- Concealment
- Natural movement
- Choice of microclimate
For this shy species, security itself is an important form of enrichment.
Diet
Red-Eyed Crocodile Skinks are primarily invertebrate feeders.
A varied diet is preferable to relying upon one feeder species.
Suitable foods can include:
- Crickets
- Small locusts
- Appropriately sized captive-bred roaches
- Earthworms
- Black soldier fly larvae
- Silkworms
- Small mealworms
- Occasional waxworms
- Other suitable captive-reared invertebrates
Prey should be appropriately sized for the animal.
Feeding Frequency
Feeding should be adjusted according to:
- Age
- Growth
- Body condition
- Prey size
- Reproductive status
- Individual appetite
Growing juveniles can be offered appropriately sized food frequently in small quantities, while established adults generally require less frequent feeding.
Rather than feeding according to a rigid schedule, monitor the individual animal’s growth and body condition and adjust accordingly.
Uneaten feeder insects should not remain in the enclosure indefinitely.
Crickets in particular may injure resting reptiles.
Gut Loading & Supplementation
Feeder insects should be appropriately gut-loaded before being offered.
Calcium supplementation is important.
Use an appropriate reptile calcium supplement regularly.
A suitable reptile multivitamin should also be provided according to the manufacturer’s directions.
The exact supplementation programme depends partly upon:
- Diet
- UVB provision
- Animal age
- Reproductive status
- Product formulation
Breeding females require particularly careful attention to calcium intake.
More supplementation is not automatically better.
Temperament
Red-Eyed Crocodile Skinks are naturally shy and secretive.
When frightened they may:
- Freeze
- Attempt to flee
- Vocalise
- Struggle
- Bite
- Become extremely still
Tribolonotus gracilis is notable among skinks for its ability to vocalise.
A constantly visible or highly exposed animal is not necessarily displaying desirable behaviour; appropriate husbandry should allow the animal to hide whenever it chooses.
Handling
Red-Eyed Crocodile Skinks should generally be regarded as display animals rather than handling pets.
Frequent handling can cause unnecessary stress.
Handling should primarily be limited to situations such as:
- Health examinations
- Enclosure transfers
- Veterinary treatment
- Essential husbandry procedures
When handling is necessary, support the animal gently and securely.
Never grab or restrain the animal by its tail.
Cohabitation
Individual housing provides the greatest control over:
- Feeding
- Body condition
- Health monitoring
- Stress
- Reproduction
Compatible male/female pairs are sometimes maintained successfully, but compatibility should never be assumed.
Adult males should generally not be housed together.
Animals maintained together must be monitored for:
- Chasing
- Biting
- Feeding suppression
- Weight loss
- Persistent hiding
- Injuries
- Reproductive stress
Any animal being bullied or losing condition should be separated immediately.
Sexing
Sexual differences become more apparent as animals mature.
Adult males develop characteristic enlarged pore-bearing structures associated with the second and third toes of the hind feet.
These structures are absent or substantially less developed in females.
Other characteristics may provide supporting clues, but animals should not be definitively sexed using general body appearance alone.
Sexing very young animals can be difficult.
Reproduction
Red-Eyed Crocodile Skinks are egg-laying reptiles.
Their reproductive biology is unusual compared with many commonly kept lizards.
Females typically produce a single egg at a time rather than a large clutch.
Multiple eggs may be produced sequentially across a breeding season.
Breeding should only be attempted with:
- Healthy mature animals
- Appropriate body condition
- Adequate calcium reserves
- Suitable environmental conditions
Egg Laying
Females require access to suitable humid nesting areas.
Eggs may be deposited:
- Within substrate
- Beneath bark
- Beneath logs
- Within other protected humid retreats
The nesting environment should remain moist but not saturated.
Disturbance around an egg should be minimised.
Incubation
Red-Eyed Crocodile Skink eggs should not be incubated excessively hot.
A commonly used incubation range is approximately:
24–26°C
Incubation commonly takes approximately:
60–90+ days
depending upon temperature and individual development.
The incubation medium should remain appropriately humid without becoming waterlogged.
Eggs should not be unnecessarily rotated after development has begun.
Stable moderate temperatures are preferable to attempting to accelerate development with excessive heat.
Hatchlings
Hatchlings are small and can be particularly vulnerable to:
- Dehydration
- Excessive heat
- Competition
- Inappropriate prey size
Provide:
- High humidity
- Good ventilation
- Extensive cover
- Shallow accessible water
- Appropriately sized live prey
- Suitable supplementation
- Low-level UVB
- Stable moderate temperatures
Young animals should be monitored carefully for:
- Feeding
- Growth
- Hydration
- Shedding
- Normal activity
Individual rearing makes monitoring each hatchling easier.
Parental Behaviour
Tribolonotus species are unusual among lizards because aspects of parental and social behaviour have been observed.
Adults may remain near nesting sites and young animals in circumstances where many other reptiles would provide no parental association.
However, captive keepers should not assume that every adult will safely tolerate hatchlings.
If young are left with adults, they require very close monitoring.
Individual rearing remains the simplest way to monitor feeding and development accurately.
Shedding
Appropriate humidity and hydration normally support healthy shedding.
Problems may occur around:
- Toes
- Feet
- Tail
- Other extremities
Repeated retained shed should prompt review of:
- Humidity
- Hydration
- Substrate moisture
- Overall health
Persistent problems require veterinary assessment.
Health
Potential health concerns include:
- Dehydration
- Heat stress
- Respiratory disease
- Skin infections
- Retained shed
- External parasites
- Internal parasites
- Nutritional deficiencies
- Metabolic bone disease
- Reproductive complications
- Stress-related decline
Warning signs include:
- Significant weight loss
- Persistent refusal to feed
- Abnormal swelling
- Laboured breathing
- Nasal discharge
- Weakness
- Tremors
- Poor coordination
- Persistent abnormal soaking
- Skin lesions
- Significant behavioural change
Serious or persistent symptoms require assessment by a suitably experienced exotic/reptile veterinarian.
Heat Stress
Excessive temperature is an important risk with this species.
Possible warning signs can include:
- Persistent attempts to escape
- Remaining constantly in the coolest area
- Unusual prolonged soaking
- Restlessness
- Weakness or lethargy in severe cases
Temperatures should be checked immediately if overheating is suspected.
The animal must always have access to cool, humid shelter.
Dehydration
High humidity does not automatically guarantee appropriate hydration.
Animals require:
- Fresh water
- Moist retreats
- Appropriate substrate
- Suitable humidity
- Regular access to drinking droplets
Juveniles can be particularly vulnerable to dehydration.
Quarantine
All newly acquired Red-Eyed Crocodile Skinks should undergo appropriate quarantine away from established reptiles.
During quarantine:
- Record body weight
- Monitor feeding
- Examine faeces
- Check skin
- Monitor breathing
- Observe behaviour
- Check for external parasites
- Maintain separate equipment
Veterinary faecal testing may be particularly worthwhile where an animal’s previous history or origin is uncertain.
Captive-Bred Animals
Captive-bred animals should be strongly preferred.
Before acquisition, establish where possible:
- Captive-bred status
- Age
- Sex
- Feeding history
- Health history
- Previous husbandry
- Parentage where available
Wild-caught animals may carry additional risks including:
- Parasites
- Dehydration
- Stress
- Poor acclimation
- Unknown history
Supporting established captive breeding reduces reliance upon wild collection.
Responsible Ownership
Before acquiring a Red-Eyed Crocodile Skink, consider:
- High humidity requirements
- Sensitivity to excessive heat
- Need for extensive cover
- Requirement for live invertebrate prey
- Limited suitability for handling
- Specialist veterinary care
- Long-term commitment
Their unusual appearance should not be the sole reason for acquisition.
They are most rewarding for keepers who appreciate natural behaviour and are comfortable maintaining a reptile that may spend considerable periods hidden.
Summary
The Red-Eyed Crocodile Skink is a fascinating tropical forest-floor lizard whose husbandry differs considerably from that of many commonly kept basking species.
Successful care depends upon providing moderate temperatures, high humidity combined with good ventilation, deep moist substrate, extensive leaf litter and cover, clean shallow water, low-level UVB, varied appropriately supplemented invertebrate prey and minimal unnecessary handling.
Temperatures should not be allowed to become excessively high, and the enclosure should always provide cool, humid retreats.
A heavily planted naturalistic enclosure that allows the animal to remain concealed while choosing between different microclimates is ideal.
With responsible sourcing and appropriate husbandry, Tribolonotus gracilis can be a fascinating long-term display species.
IMPORTANT INFORMATION
This care sheet provides general husbandry guidance and does not replace species-specific research or veterinary advice. Individual requirements may vary.
If you have concerns about an animal’s health or care, consult a suitably experienced exotic or reptile veterinarian.
Information correct at the date of publication.
reptilecommunity.com | Revised: August 2026