Blotched blue-tongued lizard
The blotched blue-tongued lizard (Tiliqua nigrolutea) is one member of a genus of blue-tongued skinks which is endemic to southeastern Australia. This animal has a fleshy blue tongue which is used to taste the air and scare off potential predators. It is a robust and relatively large member of the skink family (Scincidae) that tends to rely on camouflage and bluff as its primary means of defence. However, if cornered or molested, it can put on an impressive and effective defensive display. If further molested, it will bite, but mainly as a last resort; although the bite is painful due to its powerful jaws, the teeth are blunt and generally do not break the skin. The species is harmless, as all skinks and are inoffensive by nature, often being kept as pets due to its appealing, inquisitive nature and readiness to become tame.
The lizard is about 35 to 50 cm long, and is found in wet and dry sclerophyll forests, montane woodlands and coastal heathlands. It is an omnivore with a diet consisting of leaves, flowers, fruit, slow-moving invertebrates, and small vertebrates. The tail can be dropped (autotomy) when grasped by a predator (like most skinks), but this large skink is much less likely to do so than other members of the skink family.
They are found in southeastern parts of Australia, including Tasmania and the islands of Bass Strait. In the northern parts of their range, such as the central tablelands of NSW, they are generally restricted to highland areas, whereas in southern Victoria and Tasmania, they can be found along the coast. Some herpetologists describe two distinct forms of this species - a highland or alpine form and a lowland or southern form. Specimens from the northern parts of the species range (alpine form) are generally larger, blacker and tend to have more colourful blotches on their backs, which are sometimes pale pink, salmon-pink or orange in colour.
Blotched blue-tongued lizards emerge from brumation in early spring, which is the mating season. These large skinks are viviparous (give birth to live young), with the highland/alpine form giving birth to relatively larger and fewer young (~5-6) compared to the lowland form (~10-12). The young are usually born in autumn, after a relatively long gestation period. They are also relatively long-lived (anecdotally 20 years or more) compared to many of the smaller skink species. They have adapted well to some rural and urban areas, where they can be found living on farms and in gardens where they are an asset, as they love to eat pests like snails, slugs and occasionally rodents.
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- Edwards A., Jones S.M. and Davies N.W. (2002). A possible alternative to 17β-estradiol in a viviparous lizard, Tiliqua nigrolutea. Gen. Comp. Endocrinol. 129 114-121.
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- Gartrell B.D., Girling, J.E., Edwards A., and Jones S.M. (2002). Comparison of noninvasive methods for the evaluation of female reproductive condition in a large viviparous lizard, Tiliqua nigrolutea. Zoo Biol. 21 253-268.
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- Edwards A. and Jones S.M. (2001). Changes in plasma progesterone, estrogen and testosterone concentrations throughout the annual reproductive cycle in female viviparous blue-tongued skinks, Tiliqua nigrolutea, (Scincidae), in Tasmania. Gen. Comp. Endocrinol. 122 260-269.
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