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Blue-tongued Lizard

Classification, Identification

Blue-tongued lizards are the largest members of the skink family (Scincidae). Skink lizards have overlapping scales that are usually smooth and contain small plates of bone. There are more than 300 species of skinks in Australia. Australia has six species of blue-tongued lizards and three are common and widespread in New South Wales. The Eastern Blue-tongue is silvery-gray with broad dark brown or blackish bands across the back and tail. Individuals on the coast usually have a black stripe between the eye and the ear that may extend along the side of the neck. The belly of blue-tongues is usually pale with darker variegations. The eye is small and reddish-brown to gray. The tongue is dark blue and the lining of the mouth is bright pink. Blue-tongues have a long body, large head and short legs and toes. The tail is shorter than the body and generally tapers evenly to a point. Male blue-tongues have a proportionally larger head and stockier body than females but females grow slightly bigger than males. The Eastern Blue-tongue can grow to almost 24in total length

Distribution

Blue-tongues usually live in open country with lots of ground cover such as grasses or leaf litter. They shelter at night among leaf litter or under large objects on the ground such as rocks and logs. Early in the morning blue-tongues emerge to bask in sunny areas before foraging for food during the warmer parts of the day. Like all lizards, blue-tongues do not produce their own body heat, and rely on the warmth of their surroundings to raise their body temperature. Blue-tongues maintain a body temperature of about 30-35C when active. During cold weather they remain inactive, buried deep in their shelter sites, but on sunny days they may emerge to bask. Blue-tongues eat a wide variety of both plants and animals; Blue-tongues are not very agile and the animals they eat are mostly slow moving. Their teeth are large and they have strong jaw muscles so they can crush snail shells and beetles. When threatened, blue-tongues turn towards the threat, open their mouth wide and stick out their broad blue tongue that contrasts vividly with the pink mouth. This display, together with the large size of the head, may frighten off predators. If the threat does not go away, blue-tongues may hiss and flatten out the body, making them look bigger. A frightened blue-tongue may bite if it is picked up. A bite from an adult blue-tongue can cause pain, break the skin and leave a bruise but there is no venom and hence no long-term ill effect. However the bite site should be cleaned with a mild disinfectant, as with any animal bite. If handled roughly by their tail, Eastern Blue-tongues, particularly young ones, may drop the tail. The tail stump rapidly heals and a shorter regenerated tail grows back after a while

Parasites and Predators

Reptile ticks are commonly found on blue-tongues; they attach under the scales and in the ear canal. In the bush the major predators of blue-tongues are large predatory birds (such as Brown Falcons and Laughing Kookaburras) and large snakes (including the Eastern Brown Snake, Red-bellied Black Snake and Mulga Snake). Feral cats and dogs also eat blue-tongues.

Reproduction, Growth and Life Span

Blue-tongues live alone for most of the year, but between September and November (in Australia) males pursue females and mating occurs. At this time, males may fight aggressively among themselves. Mating may be rough, with females carrying scrape marks from the male's teeth. Female blue-tongues give birth three to five months after mating, between December and April. At birth, the young eat the placental membranes, and within a few days shed their skin for the first time. The young are ready to look after themselves straight after birth, and disperse within a few days. Eastern Blue-tongues probably become adults at about three years of age when they have a total length of about 16. Blue-tongues are long-lived. Several captive animals have lived for 20 years.

Blue-tongues in suburbia

In the Sydney region, the Eastern Blue-tongue occurs on the coastal plain and in the lower Blue Mountains and the Blotched Blue-tongue occurs in the higher parts of the Blue Mountains. Adult blue-tongues adapt well to suburbs where there are large backyards with plenty of shelter. They rapidly become used to human activity, and may live in the same place for many years. Rockeries, horizontal pipes and the cavities under houses are favorite hiding places; sunny paths and lawns provide basking sites. Plenty of food such as snails, slugs and caterpillars is usually available in gardens, and a blue-tongue in the garden will help to keep down the number of snails and plant-eating insects. Look out for blue-tongues when mowing long grass! They will try to escape the lawn mower by hiding in the grass rather than running away. Blue-tongues like to bask on warm surfaces, and black tar roads, which warm up quickly in the sun "lure" many to their deaths. Young blue-tongues are easy prey for suburban dogs and cats, as well as predatory birds like kookaburras. Most young blue-tongues in suburban gardens probably do not reach adulthood. Large dogs also kill a few adult blue-tongues, although the thick bony scales of the adults protect them from many animal bites. When threatened, a Funnel web rocks back on its hind legs and lets venom drip down its fangs. A dog raises its hackles, growls and bears its teeth. The Blue-Tongue shows it has a big blue tongue. To reinforce the bluff, the lizard stands its ground, hissing and drawing as much attention to the tongue as possible. Confronted with such an odd sight, one can't help but think that there is something to fear about tongues after all.

Housing requirements

Most hatchlings can be kept in a 10-gallon aquarium. Full sized adults should be kept in 40 to 55-gallon aquariums or similar enclosures. A temperature gradient of 75 - 85 F should be established with a basking area of 90 - 95 F during the day. Temperatures should not fall below 70 F at night. Heat/Light: Temperatures can be maintained with basking bulbs, infrared heat bulbs, and ceramic emitters or under tank heaters and panels. Hot rocks should never be used due to the high risk of burns that can be inflicted on the animal from malfunctioning heat rocks. As with most diurnal species full spectrum light is required. Wood shavings (avoid cedar or pine as these may cause long term health issues), lizard litter, newspaper or indoor/outdoor carpeting can all be used as substrates. Environment: Most blue-tongued skinks available in the pet trade are ground dwellers and do not require many rocks or braches for climbing. A hide box should be provided for the animal as well as a portion of the enclosure maintained with slightly damp substrate such as sphagnum moss to provide a humidity chamber to help with shedding. The enclosure should be spot cleaned daily. A thorough cleaning should be performed on a regular basis. A 5% bleach solution is an excellent disinfectant. Be sure to thoroughly rinse the enclosure before replacing the substrate and placing the lizard back in the enclosure.

Diet

Most blue tongues skinks are omnivorous (eating both plant and animal matter). Generally a diet consisting of 60% plant and 40% animal will provide a healthy mix for your animal. Frozen mixed vegetables, various greens, small amounts of high quality dog food, crickets, mealworms, and thawed pre-killed frozen mice can all be fed to your skink. Fresh water should be provided daily.