Biology
Blue-tongue skinks are forest floor dwelling lizards with large, smooth, flat scales, a wide head, and a bright blue tongue. These lizards can grow to around 50 to 60 cm in length and can live for longer than 10 years. They are omnivores and will eat a very wide range of foods including plant matter and live insects. In the wild, they will also eat carrion and any mammals, reptiles, birds, or amphibians they can find, though snails are their main food source and should be included in captivity.
Before getting a blue-tongue skink (BTS) you must be sure that you are able to provide the correct care and associated costs for its whole life. There are many species and subspecies available, so you must be sure to have correctly identified the species you keep. Some are farmed in their native range, but you should only obtain a skink bred in captivity in this country.
Environment
The vivarium must be secure to prevent escape and free from hazards. A minimum 120 cm long by 75 cm high by 75 cm deep vivarium made from a solid, sealed material is advised for a single BTS. Good ventilation is essential to reduce the risk of bacterial build-up and infections. The vivarium should be placed in a safe location away from drafts, heat, and direct sunlight to avoid temperature changes.
Temperature
Reptiles are ectothermic meaning they use their environment to warm up and cool down, so you need to create a thermogradient. This means positioning the heat source at one end of the vivarium, leaving the other end cooler, so the reptile can move around to regulate its body temperature.
Create a ‘basking zone’ for your skink - the warmest area in the vivarium. Use a suitable wattage halogen heat lamp or ceramic (non-light emitting) heater, pointing downwards. Heat lamps must be guarded to prevent burns, or injuries in case the bulb shatters.
A thermostat must be used with all heat sources. This is a simple device that measures the temperature and prevents the vivarium overheating, via a probe placed above the substrate. Adjust the thermostat temperature and check with a digital thermometer that the basking zone is between 30 to 32oC, up to 35oC for younger skinks. The cool end should measure 22 to 25oC. The temperature should only drop to 20 to 22oC at night so you may need to fit a ceramic heater with a thermostat.
Thermostats are not always accurate, so it is essential to check the maximum and minimum temperatures daily. Place the probe of one digital thermometer at the cool end and another at the basking zone. An infrared thermometer can also be used to check the temperature in the basking zone and cool end daily. Skinks are diurnal (awake during the day) and like to bask half covered with substrate. They may also spend time out in the open, especially in the morning. Your skink will benefit from a wide stone placed in the basking zone. Choose a stone around 30 cm across to provide a secure platform but do not allow the skink’s back to get closer than 25 cm to the heat source.
Humidity
A hygrometer should be purchased to measure the humidity at the cool end of the enclosure. Blue-tongue skinks originate from many different localities, each with their own specific humidity. Humidity levels should be provided as appropriate for your exact species and locality. You can boost humidity by spraying the enclosure with clean, filtered water. If it is too high, the vivarium will need more ventilation.
Light
Reptiles use natural daylight to set their day and night patterns. Blue-tongue skinks have fairly thick skin that offers some protection from the sun in the wild, so we need to provide an adequate source of light including ultraviolet (UV). Blue-tongue skinks can see part of UV light, called UVA, essential for their colour vision. Another very important part is UVB, which allows the lizard to make vitamin D3. Vitamin D3 allows the lizard to store and use calcium, an essential mineral - just like humans!
UVB does not pass through glass windows so do not place the vivarium near a window. Instead, a reptile UVB lamp must be used inside the vivarium.
Create a ‘photogradient’, from light to shade, by positioning your light source close to the basking zone. In a vivarium of 60 cm height, a 6% UVB tube, around half the length of the vivarium, should be fixed into the roof of the vivarium as far into the hot end as possible. Use a reflector of the correct length to direct the light onto your skink.
The UVB output decreases over time so the UVB output should be checked regularly, using an appropriate UV Index (UVI) meter positioned at the level of the animal directed towards the UV lamp. Blue-tongue skinks require a gradient of UVB within their enclosure ranging from UVI 3.0-5.0 in the basking zone to zero in the shade.
Some morphs of blue-tongue skinks, like albinos, will need lower UVB levels, with a gradient from 0 in the shade to a maximum of 3.0 in their basking zone. The lamp must also be replaced according to the manufacturer’s instructions.
UV lamps must always be guarded to prevent burns, or injuries should the bulb shatter. Turn off all lights at night. Lamps can be controlled using a simple plug-in timer: 12 hours on during the day and 12 hours off at night.
Cleaning
Poorly maintained enclosures can become dirty quickly and create a health risk for you and your pet. BTS droppings are quite wet and will be made up from faecal waste (the dark part) and urates (the white part). Waste should be ‘spot cleaned’ as soon as it appears. The vivarium should be completely cleaned with a reptile-safe disinfectant once a month. Carefully wipe the walls, glass, and decoration. Reptiles can carry Salmonella, so wash your hands before and after cleaning or handling to prevent the spread of infection.
Diet
Water
Water is essential to the health and wellbeing of the blue-tongue skink. A large, shallow dish should be provided at all times with clean, fresh water placed in the cool end. Some skinks will drink standing water but if not, you should lightly spray the vivarium with water every day or every other day, depending on the humidity, to allow the skink to collect droplets of water to drink as they do in the wild. Replace the water every day and if your skink goes to the toilet in the bowl.
Feeding
Blue-tongue skinks are omnivorous, meaning their diet should contain both plant and animal matter. Adult diets should consist of approximately 50-60% animal matter and 40-50% vegetables. Fruit should form no more than 10% of the diet. Varied, appropriately sized, live insects should be provided, such as crickets (e.g. brown house crickets), ‘calciworms’, ‘waxmoth larvae’, fruit beetle grubs, Dubia cockroaches, silkworms, and locusts.
Any uneaten crickets or locusts should be removed as they can bite the skink. Eggs, canned dog food of an appropriate brand and meat such as ground turkey, chicken and lean beef may also be provided. Frozen and thawed pinky rats and fuzzy mice should only be used as a treat.
You need to research the safe plants, vegetables and fruits to feed. Avoid feeding too much spinach as this interferes with calcium absorption. Also avoid too much kale as this can affect hormone production. Remove uneaten green food every day and replace with fresh.
An alternative option to the diet above is to use an appropriate formulated reptile diet for omnivores, which has the correct ratio of animal and plant matter. These are usually powdered diets that you mix with water.
Feeder insects should be kept in a large, well-ventilated container. They should be fed safe vegetables and hydrated well for their own welfare and so that the nutrients are passed onto the skink. Feeder insects should also be ‘gut-loaded’ with vitamins and minerals by offering them an appropriate formulated gut-loading diet 24-48 hours prior to feeding them to your skink.
The captive environment does not supply all the vitamins and minerals available in the wild, so you also need to dust the food lightly with supplement powders. Ask your reptile vet for help with this. Vitamins or minerals can be overdosed so always follow the instructions. For example, with a well-set UV system you do not need to provide high dietary D3 levels.
Live or tinned snails can be purchased from reptile shops. These greatly enrich the diet and behaviour of the skink. Do not feed snails directly from outside, because they can contain pesticides or parasites. Cracked quail eggs can help provide essential calcium and vitamin A as part of a varied diet.
Blue-tongue skinks can easily suffer with obesity in captivity. This can be due to a high protein diet and restricted exercise. It's a good idea to weigh your skink once a month. Young skinks grow very quickly and will benefit from a little and often approach to feeding.
Behaviour
Enrichment
It is important to provide opportunities for natural behaviour in captivity, called ‘enrichment’. Provide stones and branches for climbing. Appropriately sized hides or caves are essential for skinks to feel secure and should be placed in both hot and cool ends of the vivarium. Also provide a moist hide to create an area of higher humidity by filling a hide with moss that is kept damp by spraying with clean water.
Substrate
Substrate is the name for the floor covering in your vivarium. It is important as it permits natural behaviours. You need to use a thick layer of substrate - about 4 inches - as blue-tongue skinks like to burrow. This will not only provide physical enrichment but will also reduce stress and help them to self-regulate humidity.
You can use an organic natural soil or soil/sand mix as substrate. Do not use unnatural or indigestible substrates such as ‘calci-sand’, beech chips, corn cob granules or crushed walnut shells. They are dangerous because they can clog the digestive tract and cause a blockage in a condition called ‘impaction’. For permanent housing, we recommend that owners provide a naturalistic environment and consider a bioactive system.
Keepers can research how to do this using expert books on the topic, or specialist keeper member groups online.
Company
It is advised that you keep skinks separately due to their territorial nature. When housed together, they can bite each other’s feet or even kill each other.
Reptiles should not be removed from the vivarium for so long that their core temperature drops. Around ten to fifteen minutes is a safe period for this, depending on the temperature outside of the vivarium. Bluetongues have quite sharp nails so take care that they do not get them stuck in carpet or clothing.
Handling
Blue-tongue skinks can tolerate human interaction and handling after settling in. They do have a fairly strong bite and need time to get used to you. Never grab them as this can cause stress. The skink should be gently scooped up with both hands, so all four legs are supported. If your skink backs away from you or opens its mouth to display its tongue, it is better to wait for another time.
Health and welfare
A healthy skink should have smooth, glossy scales, a straight jaw and a thick base of the tail, as this is where essential fats are stored. You will need to register with a reptile vet, so your skink has access to check-ups and treatment as required.
Shedding
Skinks shed their skin in large pieces. There is no rule as to how often this will happen, but young, growing skinks shed their skin more frequently.
Your skink’s skin may appear dull when it is about to shed. The skin should then come away easily, ideally over a day or so. If this is not the case, try bathing the skink in tepid water, which can help soften the skin.
Poor shedding is usually due to low humidity. Consult your vet if your skink constantly has issues shedding.
Brumation
It is quite common for blue-tongue skinks to slow down in the harsher UK colder months, which is called ‘brumation’. It is triggered by the reduction in room temperatures and natural daylight hours. They will reduce the amount that they eat whilst increasing the time spent sleeping. For a healthy skink, brumation is not of concern but seek the advice of your reptile vet if your skink suddenly stops eating rather than over a long period or is losing a lot of weight.
Diseases and concerns
It is vital for skinks to have a varied, well-thought-out diet and that the heating and lighting systems are tested to be working well at all times. Look for signs of abnormal droppings: constipation or diarrhoea; or weight loss, which can be due to internal parasites. If you have any concerns, have your vet run a parasite test on a fresh sample of droppings. If the skink is spending long periods of time sitting in the water, it may be an indicator of a skin condition or mites.
One of the most common problems for captive reptiles is metabolic bone disease, ‘MBD’, a term used to describe a range of nutritional diseases. However, it is most often due to a lack of UVB lighting, resulting in vitamin D3 deficiency, preventing reptiles absorbing calcium from their food. This can cause muscle weakness and softening of the bones. The blue-tongue skink will show signs of nutritional deficiency quite quickly, for example a wave or dipping of the spine, followed by changes to the shape of the jaw.
Vitamin A deficiency can result in skin changes and secondary infection, particularly around the eyes and lips.
It is essential that you take the time to research further before obtaining a reptile. If you do get a skink, monitor its health and behaviour daily and see your reptile vet immediately if you have ANY of the above concerns.
Transport
If you need to transport your skink, it is important that it is done safely. Choose a suitable sized carrier; young lizards such as hatchlings can be transported in ventilated plastic containers with soft, absorbent paper. Adults can be transported in a well-ventilated plastic tub to prevent injury. This should be kept warm; the addition of a heat pack may be required but make sure this will not over-heat. Keep transit time to a minimum to reduce stress.
Bringing your lizard home
Set up the vivarium and run it for a minimum of one week before introducing your skink. This will allow time for any faults to develop and be fixed and for you to learn how to maintain the system before the animal arrives.
On the first day, carefully allow the skink to climb into the vivarium. Leave your new pet with some food and water but with no further interaction until the following day. It is best not to do lots of handling for the first week, instead, allow the skink to explore in its own time.
