The Eastern Blue-tongue, Tiliqua scincoides, is greyish brown, with between 7 and 10 darker bars across the body. It is a large skink, growing to a snout vent length of 290 mm.
Common Blue-Tongue LizardPhotographer: Peter Robertson / Source: Wildlife Profiles Pty. Ltd.
Although more common on the basalt plains to the west of Melbourne, Common Blue-tongue Lizards are also found on the Mornington Peninsula. They are usually found basking or sheltering under cover such as fallen logs, or discarded rubbish such as timber or iron.
Their diet consists of both plant and animal material, such as snails. Females give birth to as many as 25 live young in a litter.
Cogger, H. 2000. Reptiles and Amphibians of Australia. Reed Books.
Wilson, S. & Swan, G. 2003. Reptiles of Australia. Princeton University Press.
If you are within the Blue-tongue Lizard's natural range (ie the environmental conditions are within the limits it's used to) and there are no marauding cats or dogs, then the chances of survival to adulthood are excellent. The main threat to young lizards in this situation is predatory birds such as Kookaburras, birds of prey and even Butcherbirds. It's better when lizards naturally colonise an area because they are attracted to suitable locations that suit them, rather than being artificially released into areas that may not suit them. However, most gardens have enough food available for Blue-tongues, and if it ever finds the conditions unsuitable it will no doubt move to a more favourable location.
Chicken eggs are not naturally part of a Blue-tongue’s diet – although they naturally take smaller eggs, chicken eggs are generally too big. However, once they get a taste for chicken eggs it can be hard to wean them off. If you’re able to fence off the chickens or their laying area from the rest of the garden, it should be relatively easy to keep Blue-tongues out. Due to their thick bodies and stumpy legs, Blue-tongues are unable to climb any vertical surface greater than about 30cm high.
There are a number of Blue-tongue species, each with slightly different breeding seasons, but in general it is between December and April. Males can do a lot of damage to females, so as the carer of the lizards this is something that shouldn’t be taken lightly and they should be separated if it gets out of hand, as males are capable of killing females. The problem may be a lack of hibernation (also called brumation) – this is usually required by females for their ovaries to mature. Without brumation, the female may be incapable of mating which means the male will not let up with her. In this case they should be separated at least until the female is capable of mating.
Ultraviolet light is a complex issue for reptiles, and the more we learn about the relationship the more complicated it gets. Reptiles need UV to build calcium in their bones and avoid metabolic bone disease, but it can also be supplemented through non-UV sources such as calcium powder. It’s complicated because, for example, UV can only be absorbed when the lizard is warm, so placing a UV lamp at one end of the enclosure and a basking light or heat mat at the other end means no UV is absorbed. Artificial UV sources aren’t always the answer either – lamps from different manufacturers emit different quantities, wavelengths and types of UV. And some types of lamp lose their UV capacity more quickly than others. The best option is unfiltered sunlight, at least four hours per day, and the easiest way to achieve this is spending time outside during summer. Make sure the lizard has places to hide and places to bask, so it doesn’t overheat and can choose the best location for itself.
Frequency of defecation is determined in part by how often the lizard eats – it’s usually 2-3 times per week. Even during winter when they hibernate they will defecate once or twice.
Blue-tongue Lizards (Tiliqua species) can be kept without a permit but must be bought from a pet shop, never collected from the wild. The ‘wild’ includes your own backyard, and the rules are in place to protect local populations and prevent the inappropriate mixing of gene pools. So it’s best to put the lizard back and leave her to her own devices. It is difficult to tell whether a female is pregnant (gravid) as the weight of an individual varies over time, and increases quickly in spring as they come out of hibernation (brumation) and fatten up in preparation for breeding. Young females may also become pregnant and produce only a couple of stillborn rather than the 10 or more living young that an older will produce, or may reabsorb the foetuses before giving birth. One of the best ways to tell if a female is pregnant is if her breathing becomes heavy as the foetuses press against the lungs, and during later pregnancy she will become very fat and very slow.
Please be aware that keeping wildlife as pets, such as Blue Tongue lizards collected from the wild, is subject to strict licensing requirements and legislation - please contact your State or Territory government for further information. Blue Tongues can be kept without a licence as long as they are purchased from a pet shop or licenced breeder. It is illegal to collect them from the wild - even from your own backyard.
Hi Anthony, During winter, Blue-tongues will naturally hibernate (called brumation in reptiles) when the temperature starts to drop. If the lizard is kept inside all year, the lizard will not brumate and there are no adverse effects from this. So it’s up to you if you want your lizard to brumate/hibernate or not. The only other factor to keep in mind is that adult lizards need to brumate at a minimum temperature (usually 15 degrees or less) for a minimum amount of time (usually six weeks) to develop their reproductive organs, so if you want to breed your lizard then brumation is necessary.
Hi Shan,Blue-tongue Lizards (Tiliqua species) feed well in captivity on insects (crickets and cockroaches in particular), snails (guaranteed free of snail pellets), fruits, vegetables and greens. They need either calcium dusted crickets or access to natural light or significant amounts of artificial ultraviolet light each day to avoid bone and skeletal problems. Some lizard keepers will boost the crickets with other supplements, but generally this is not necessary if the lizard is on a balanced diet. During winter, Blue-tongues will naturally hibernate (called brumation in reptiles) when the temperature starts to drop. If the lizard is kept inside all year, the lizard will not brumate and there are no adverse effects from this. It is not true that if they go into brumation they will never wake up, although if brumating outside some individuals may develop infections (analogous to the common cold) that may affect their health. So it’s up to you if you want your lizard to brumate/hibernate or not. The only other factor to keep in mind is that adult lizards need to brumate at a minimum temperature (usually 15 degrees or less) for a minimum amount of time (usually six weeks) to develop their reproductive organs, so if you want to breed your lizard then brumation is necessary.
Hi Danae - we checked this with our Live Exhibits team, who have said it's best not to give Blue-tongue Skinks (Tiliqua species) any yoghurt at all. They should be fed fresh vegetables and live insects, as well as other invertebrates such as snails, and can be given fruit as a treat.
Biting is common in mature Blue-tongue Lizards during the breeding season, but as these lizards do not mature until about four years of age, that’s unlikely to be the case here. Sometimes individual animals simply don’t get on with other animals, particularly when they are held captive together with nowhere to get away on their own. You could supply add more hiding places in the enclosure and the fighting may settle down over time, or the smaller lizard may put on a growth spurt and be better able to defend itself, but the fact may be that these two animals aren’t compatible.
Hi Anthony, there are many reasons your Blue-tongue Lizard may be unwell - old age, lack of calcium, lack of UV, poor diet, infection etc. There are many specialist vets and the treatment for these ailments are usually quick and effective. It's worthwhile taking the reptile to the vet as its quality of life is likely to be dramatically improved.
Male Blue-tongue Lizards are more territorial and more aggressive than females and the level of aggression depends to a large part on the individual. In the wild they are largely solitary, and keeping them together can cause stress and serious fights. Individuals frequently lose toes or entire feet in captivity, and males can do serious damage to females during the breeding season. I you plan to introduce a new individual, particularly a young one, you should monitor their behaviour very closely - it can only take a few minutes for one of the older skinks to do major damage to the young one. You should also have an extra enclosure on stand by and be prepared to keep the new skink separately, possibly for the rest of its life.
Hi Annie, we checked with our Live Exhibits team, and they've responded as follows:
The health of wild Blue-tongue Lizards (Tiliqua species) varies over time, depending in part on environmental conditions and food availability. They also get slower and begin ailing as they get old. You could take it to a vet that specialises in reptiles, but even if the vet can help the lizard it will still need to be released afterwards. The best option may be to leave them to their natural fates.
The sloughs are from the mites rather than from the reptile. Mites are small, spider-like creatures that shed their skins (slough) as they grow, as do all arthropods. There are a couple of species of mites that infest reptiles in captivity, and they should be removed as soon as possible or they can quickly cause problems. The white mite sloughs are the most visible sign of a mite infestation.
Hi Sarah - our Live Exhibits Manager says that how well the Blue-tongue Lizards get on will depend on the sexes. If you have a male and a female or two females, they should be fine. If you have two males, they will most likely fight each other. Sexing is possible but can be difficult - there is plenty of information on this page. It is currently the mating season and courtship can be a very rough affair for female Blue-tongues (leaving bite marks, scratch marks etc), but this is normal behaviour and is not as damaging as fighting between two males.
There are a number of potential culprits that would steal eggs. Foxes are the most likely, but they would also be stealing your chickens if they had the opportunity. Brushtail Possums and rats will take the eggs but not the chickens. Blue-tongue Lizards would not be able to climb a barrier of 60cm, but most snakes would have little problem with this. If you can sweep the area with a broom at the end of the day, any tracks around the nesting boxes the following day may give you a clue.
Blue-tongue Lizards will often live more than 20 years. You mention that you've had the lizard for seven years but don't indicate how old it actually is. It's not always possible to determine an old lizard by its appearance, so it can be difficult to estimate age without knowing exactly when it was born. Blue-tongues are most vulnerable during or immediately after hibernation - if you've hibernated the lizard over winter it may have picked up an infection and now succumbed. This is the most common cause of death in the wild. Otherwise the issue may simply be old age.
It's health may improve if you keep it indoors, particularly during cold weather - other than that, it will continue to inevitably decline.
Blue-tongue Lizards attacked by pets don’t have a particularly good survival rate unless treated by a vet and given antibiotics and other medication. As it’s a wild animal, it is your decision whether or not to take the lizard to the vet. There are a number of specialist reptile vets around Melbourne, and also a number of vets who treat wild native animals for a minimal fee.
Although it's been acknowledged for a long time that Blue-tongue Lizards eat plant material, there are very few records about which species they will eat. Almost all captive animals are fed vegetable matter in the form of fruits and vegetables, and observations of the dietary habits of wild specimens are few and far between. What little information there is comes largely from analysis of scats and gut contents, and the only references to specific plant species we can find are that they consume flowers during spring and eat increasing amounts of leaf material during summer. These include the seeds of Dianella and the leaves and flowers of the introduced Medicago.
Given the paucity of available information, it may pay to trial a few plant species yourself from the lizards' natural range.
From our research, it sounds like you do have quite an elderly lizard! It is probably less likely in nature for one to live so long but it is thought they may live to thirty years, given ideal conditions and maybe a lot of luck! There are a number of references which suggest 20 years or more possible life span as with yours.
Male and female Bluetongues are very difficult to distinguish and even using a range of different features, sexing is never certain. Males, for example, have proportionately bigger heads, but females are generally bigger so may have a large head anyway. The only certain way is to see who gives birth!
Hi Scott - Blue-tongue Lizards live alone for most of the year, but between September and November males pursue females persistently and may be found together in a single burrow. This is only a temporary arrangement and we suspect that's what the adults you mentioned are doing. The smaller lizard may be unrelated or may be the offspring from a previous breeding season - Blue-tongue Lizards may live 20 years and breed every two to three years.
Blue Tongues regularly produce 20 or more offspring per birthing episode, so it's understandable that you're wondering about the appearance of a single offspring. This can sometimes happen due to several reasons - the most common seem to be low sperm production from the male, or a female at the start of her reproductive life, or one at the end of her reproductive life.
It's possible that more offspring may appear, and if they do so it will happen over the next week or so. But the most likely scenario is that no more will be born.
Hi Chloe - we checked with our Live Exhibits experts about this, and they have responded as follows:
Garden Skinks and Blue Tongue Lizards do not do well together. Whilst a Blue Tongue will live in peace with larger lizards such as dragons, it will continually chase the skinks around and, if it does not kill them, will stress them and probably make them drop their tails.
Hi Stella - we ran these questions past our live exhibits crew, who have responded as follows:
Blue Tongues in captivity will happily eat dry and wet dog food but they should not be fed cat food. There is also no good reason to feed them rice. If the enclosure is of a suitable size, Blue Tongues will live in harmony with Bearded Dragons and Shinglebacks, but male Blue Tongues should not be housed together as they will usually injure and even kill each other in a short time.
Please also be aware that reptiles in captivity should be sourced from a breeder, who should be able to provide husbandry advice, and that many species require a permit to be kept in captivity.
Hi again Stella - we ran this past our Live Exhibits team also, here's their reply:
Blue Tongue Lizards cannot be sexed with any accuracy until they are at least one year old, often older. Even then sexing can be difficult and/or unreliable, but it is definitely not possible to sex a three week old lizard.
Hi Lyn, Blue Tongue lizards don't mate for life - they will mate with any available partner, which generally changes from year to year. Lizards such as Shinglebacks will mate with the same partner each year, but will seek out others if their partner dies.
You can either move the Blue Tongue to another suitable location now (100m away should be enough), or when you're ready to have the pool area redone, move the Blue Tongue to another part of the garden and it should seek out somewhere else to shelter. Blue Tongue lizards are not generally tied to any particular location and will move if it becomes uninhabitable.
Hi Harrison, we forwarded your query to the Manager of our Live Exhibits team, and he's responded as follows:
As long as you consider the Blue Tongue to be healthy, it might just need some time to adjust to the new arrangements. With regular attention to the lizard and careful handling, it should get used to your presence once again. If you’re concerned about the lizard’s health, then a trip to the vet might help the situation.
Hope this helps
Hi Sue; we checked with our Live Exhibits manager on this, and his response is as follows:
It is possible for Blotched and Eastern Blue Tongue Lizards to mate and produce offspring, but this is an extremely rare occurrence and we don’t know of any cases where the offspring have survived to adulthood. It’s possible for a number of members of the Blue Tongue genus (Tiliqua) to hybridise, including Stumpy Tails, but it’s very rare. It would also be unusual if your lizards have mated at this time of year, even if they are being kept warm inside. So mating in this case is possible but high unlikely.
Hi Mick- we've posed this to our Live Exhibits team, who have the following reply for you:
Because blue tongue lizards occur naturally in Victoria, they are more than capable of coping with the seasons. During winter when it hibernates (or brumates, as it is sometimes referred to in reptiles), its activity and metabolism is greatly reduced, and it’s designed not to move around or feed during this period. If the lizard does eat, the body can’t digest the food and it may sit in the lizard’s stomach until the weather becomes warm enough to digest it, probably not until Spring, which can cause all sorts of problems. So the best option is to leave the blue tongue alone until it appears of its own volition later in the year
If the Blue Tongue has been living in the shed for some time, it's fairly certain it is able to get in and out as it pleases, probably through a crack in the base of the shed. Blue Tongue lizards can squeeze through surprisingly small holes. In that case the Blue Tongue won't leave through the open door when it has a more protected means of getting in and out. A shed can be an excellent shelter for Blue Tongues and it is unlikely to leave of its own accord.
If there really is no other means of entry for the lizard, the only way to remove it is to pick it up and place it in the garden. They defend themselves by hissing and other aggressive gestures, but they are harmless if you keep away from the mouth (and even then they are fairly harmless).
If there is another means of entry, the only way to keep it out is to find the entrance and block it, then physically remove the lizard.
But it sounds like an excellent example of peaceful coexistence in a backyard.
Hi Justin,We forwarded your question to Museum Victoria’s Live Exhibits team who provided us with the following information:There are many internet sites solely dedicated to the sale of reptiles. A quick web search should provide you with plenty to choose from. Most reptile forums also have a for sale section that may be useful. Other places to try are some of the local pet shops that deal in reptiles.As it is domesticated it should not be released back into the wild.
Hi Anne, Blue tongues are omnivores and will eat a wide range of food – from fruit, veggies and any animals that they can get their mouths around. In a normal situation I would imagine that a frog can jump away far more quickly than a blue tongue lizard can hunt so they should be safe living in your courtyard.
We love receiving comments, but can’t always respond.
Hi Britt, blue tongues are very difficult to sex – males tend to have a slightly broader head but this is not reliable – there is no easy way to sex them.
Please be aware that you need a permit from Department of Sustainability and Environment to catch a blue tongue, as they are native animals. For details on permits see their website at www.dse.vic.gov.au.
Hi Darren, this might be easier said than done if it is moving quickly but if you can get some good quality images of the animal please feel free to email them ...
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