Authored by Larissa Lurid
Natural History of Blue Tongue Skinks
The Blue Tongue Skink (Tiliqua Scincoides) is an omnivorous, diurnal (active during the day) species of lizard, ranging from Australia to New Guinea and the island of Tasmania. This species is becoming more popular in the pet trade and is a great option for those who want a medium-sized, hardy, generally docile species. Whether you are newer to owning reptiles or are experienced, many people enjoy caring for these unique lizards.
Blue Tongue Skinks have received their name for the trait they are best recognized for, their bright blue tongue that is used for defense purposes. When feeling threatened they will puff up their body, lift their head and open their pink mouth as wide as possible to look larger, flattening out and flicking their tongue to deter predators.
The colorful mouth and tongue give the impression to other animals the skink might be venomous and should be avoided.
These lizards have long bodies set low to the ground and short legs. They are ground foragers with flexible bodies built to burrow. Their ribs can expand when basking, or contract to fit into tight spaces while hiding under a rock or going underground for safety, when sleeping, or to escape the heat. Blue Tongues generally range from 1.5 to 2 feet long and live about 15-20 years. Another interesting fact is that this species gives live birth instead of laying eggs.
Blue Tongue Species
The most common Blue Tongues found in the United States pet trade are the Northern, Irian Jaya, and Merauke. It’s best to be careful of where you purchase your skink since many can be wild caught, most commonly being Meraukes, Indonesians, Key Island, and Tanimbar. It’s always recommended to get a captive bred reptile. Wild caught are generally more aggressive, easily stressed, and often carry parasites or diseases. There are many species of Blue Tongues, such as Northern, Irian Jaya, Merauke, Indonesian, Key Island, Tanimbar, Blotched, Eastern, Western, Shingleback, Centralian, and the Adelaide Pygmy Blue Tongue. When looking for a specific type of Blue Tongue, it’s important to learn how to identify the appearance of each since many are mislabeled when being sold.
Handling and Taming:
Just as handling any other lizard, when holding a skink it’s important to make them feel secure. To properly handle, be sure to support the body, all four legs, as well as at least the base of the tail. If they don’t feel safe when being lifted, they may flail thinking they will fall and become nervous. Many are generally calm, but each has their own personality so some may need to have more time to get used to people. When adopting, make sure to let new reptiles settle in without being handled for at least one week to get used to the new environment. Being in a new home will already be stressful, so it’s important to give them time before working with them. If your skink is very nervous or doesn’t feel comfortable being held, it’s important to take things slow and gain their trust. With very nervous lizards, start out by sitting near their enclosure and even quietly talking to get them used to your presence and see you aren’t a threat. Reaching into their cage and pulling them out can make them feel as if they are being hunted and in danger. Next step would be to put your hand flat down in their cage, not trying to touch them and let them come to you or just watch to see you aren’t going to hurt them. In time they will become used to your presence and you can begin handling. When handling I would recommend to sit on a couch or bed with your skink and let them walk on your lap or around you.
Blue tongue skinks are solitary animals and must be housed alone. They will be very aggressive to any other skink in their cage which will result in injuries on the body, bitten off toes or tail, and even death. Even during breeding they must be closely watched since mating pairs can often hurt each other.
Many types of enclosures can be used for a blue tongue, from tanks, wood enclosures, melamine, etc. An adult must be housed in a 75 gallon or 4 foot long by 2 foot wide enclosure. Babies may also be housed in an adult sized enclosure, but if preferred they can start out in a 40 gallon wide tank or enclosure of the same dimensions. (36″ long, 18″ wide)
Never use a 55 gallon tank; it is a common misconception that even though it has more gallons than the 40, it has more floor space. This is not true since this size tank is mostly height and actually much less floor space than a 40 gallon wide tank. Feel free to use something larger than a 4×2 foot or 75 gallon tank, the more room provided for a skink, the better. They love to explore and will make use of any space you give them. You can find enclosures for sale in our affiliate store.
Preferred bedding is large aspen wood shavings. (Avoid the smaller cut ones) It is extremely important to only use aspen and not pine, cedar, or other types since they are toxic. Also stay away from sand, walnut shells, newspaper, and gravel. The ink from newspaper will stain their feet as well as not allow them to burrow. The other substrates can easily be ingested and cause impaction. (A blockage in their digestive tract which can lead to death) It is important that even when using other substrates to never feed in the tank. Any loose substrate can accidentally be ingested while eating. Also these substrates will not hold burrows and will be too dry for the tank. Although Blue Tongues don’t need high humidity, if the tank is too dry it can cause shedding problems which can result in old skin constricting and making toes or the end of tail fall off. Be sure to use at least 4 inches of substrate since burrowing is very important for this species. Some people use carefresh or more natural options such as coco fiber, cypress mulch, etc. (Just watch humidity levels if using carefresh, it can dry out the tank) Many people stick with aspen though since it’s cheap, easy to clean, and works best for holding burrows. Many skinks refuse to burrow into more loose substrates like coco fiber and don’t like it.
There must be at least two hides in the enclosure. One on the hot end and one on the cool end. It is important to give them options so they can properly thermoregulate their body temperature instead of being forced to hide on one end. They also need a flat, dark-colored basking rock below the heat bulb to help them utilize necessary belly heat to digest food and warm themselves to keep their metabolism and body temperature where they should be.
Heating, Humidity, Lighting and Measuring:
Heat & Humidity Levels
Blue tongue skinks require different humidity depending on the subspecies and where they originate from. Some such as northerns don’t need high humidity (around 40-50% is fine) while others such as meraukes, halmaheras and indonesians need high humidity (60-80%). When shedding, they can also be misted with a spray bottle to be sure they shed properly. If humidity is too low, they can get stuck shed which can result in lost toes or end of the tail, so if they seem to be having problems shedding, mist them once a daily as previously stated or you can give them a luke warm bath in shallow water. Be sure it’s not hot water, what feels comfortable to humans can be much too hot for reptiles. 80-84 degree water is a good temperature. As for basking spot temperature, it should be 95-100 degrees on the rock below the bulb. The ambient cage temperature should be about 70-80 degrees. If it is too cold they won’t be able to digest food (which can rot in their stomach and kill them) as well as slow down their metabolism so that they won’t want to eat. If too hot, they can be burnt. NEVER use heat rocks for your reptiles! For one they are not flat or large enough and even more importantly, they can easily burn the reptile. There have been many cases of horrible stomach burns due to people using heat rocks.
Proper heating elements would be either a daylight basking bulb, infrared bulb, or mercury vapor heat bulb. Infrared bulbs can be kept on at all times, while the daylight or mercury vapor bulbs produce a bright light that is fine 10-12 hours per day, but must be turned off at night. As long as the lizard hasn’t eaten just before lights out, it is fine to have the night-time temperature go down to 70-75 degrees at lights off. (Or you can use an infrared bulb for night heat) The advantage of using a daylight basking bulb is that they emit UVA rays. Skinks need at least UVB (which will be discussed soon) but having the UVA as well is very healthy for them. If using a mercury vapor bulb during the day, this is one bulb that emits heat, UVA, and UVB rays. It’s the healthiest option and can provide all lighting and heating needs in just one bulb.
If using any other heating options you will need to provide a separate UVB Bulb. UVB is important to prevent Metabolic Bone Disease, which will severely disfigure their bones and ruin their internal organs eventually leading to death. UVB lights must be on 10-12 hours per day, then turned off at night. To properly work they must be no higher than 12 inches above the floor of the cage. Also they must be replaced every 6 months; although the light will appear to still work, over time the UVB will run out. You can also purchase a UVB meter to make sure it’s still emitting the right amount. Ceramic heat emitters are also sometimes used, but should only be for ambient heat. This is an option to keep the tank warm at night if no other light is being used, but should never be used as a basking bulb. It throws out heat in every direction basically, but does not project it straight down like a basking bulb and will not heat up a basking spot below. It’s extremely important to be careful with this type of heating element since they don’t produce light. This can create a risk of starting a fire. If someone thinks the CHE has been turned off and sets it on the floor, a desk, etc. it can quickly burn through them. Likewise, if someone doesn’t know that it’s on and goes to touch the lamp shade, it can burn someone.
Measuring Temperature +Humidity
There are various devices used to measure heat and humidity in an enclosure. The best to use, which I recommend be used in every reptile enclosure, is a digital temperature probe. There are combine thermometer/hygrometers that measure both, or ones sold separately. Each has a small screen with a wire leading to a probe that needs to be set on the basking spot. There are digital ones that can be attached to the side of enclosures without a probe, but these only measure ambient temperature (which is fine for the middle or cool end of the tank, but will not work to measure the basking spot, which is most important) A digital hygrometer attached to the wall would work well though. There are also analogue thermometer/hygrometer meters that can be placed on the wall of the enclosure to measure ambient temperature/humidity. These I do not particularly recommend since they aren’t as accurate at measuring and they will not give a basking temperature reading. Temperature guns are another device people use, which can be handy when needing to check quickly, but should be used in addition to a digital thermometer probe that’s always in the cage so you can be sure the temperature is never too high or low.
The diet should consist of 60% dark greens and vegetables to 40% protein and just a little fruit as a treat. The healthiest staple greens and vegetables would be collard greens, mustard greens, turnip greens, escarole, dandelion greens, and various kinds of squash. For more on diet please see Dr. Bruce Bogoslavsky’s article. Never use lettuce, it contains basically no nutrients and is not healthful. Also be sure to avoid foods high in oxalates, phosphates, and goitrogens. These can cause health problems for your lizard. Do not feed citrus fruits either, they are very acidic. As for proteins, they eat both meat and insects. The best staple insect to feed is dubia roaches. They can be used for skinks of all sizes and have a good amount of calcium, protein, and little fat. Some other insects that can be fed are crickets, snails, silk worms, superworms, locusts, horn worms. Stay away from mealworms, they don’t contain much nutrients and are hard to digest for the skinks and have higher amounts of chitin. Be sure to dust insects with calcium containing D-3 twice per week and calcium without D-3 the rest of the time. Using some multivitamin powder is a good addition to the diet as well. Some people feed butterworms or waxworms as treats, but these are very fattening and should be only an occasional treat. Always be sure to gutload insects before feeding, or they won’t provide much nutrients. Gutloading is to provide the insects with food for at least 24 hours before being fed off. When keeping insects, always have vegetables, bug burger, etc. provided for food and hydration. As for meat protein, use healthy, lean meats for your skink. Lastly, remember that the key to a healthy skink is a varied diet. Other foods such as egg or rat/mouse pups can be used once a month as a treat, but should not be a regular part of the diet. Too much egg can cause a biotin deficiency and rat/mouse pups contain a lot of fat. When feeding egg, the two best options are hard-boiled or raw. Scrambling or frying would get grease or butter on them, which is not healthy for the skink. Some people choose to feed dog food as part of their meat protein. When doing so, just be sure to stick to the canned dog food and not cat food, which contains taurine. Also, only use high quality brands; the majority of canned dog foods (including all the popular brands often advertised on television) are not even healthy for the species it’s created for and contain many fillers, pulps, broth, corn, grain, ash, etc. Some of the best brands are Merrick, Wellness, Halo Pets, and Blue Buffalo. Always read the ingredients on the can; you want to see whole meats listed as the first three ingredients and do not want to see the fillers mentioned. Young skinks can eat daily, but as they grow every other day is fine.
*Special Note: Larissa can be contacted about further information Send Mail