Blue-tongued Skink

About the blue-tongued skink

The blue-tongued skink, more precisely Tiliqua scincoides, is a large lizard in the skink family, native to Australia and to Tanimbar Island in Indonesia's Maluku Province. It belongs to the subfamily Egerniinae within the family Scincidae. Three subspecies are recognized: Tiliqua scincoides scincoides, the eastern blue-tongued skink of southern and eastern Australia, first described in 1790; Tiliqua scincoides intermedia, the northern blue-tongued skink of northern Australia, described in 1955; and Tiliqua scincoides chimaera, the Tanimbar blue-tongued skink of Indonesia's Maluku Province, described in 2000. It's also known by several other common names, including common blue-tongued lizard and common bluetongue.

It is a stout-bodied, short-legged lizard that grows to more than 60 centimeters (24 inches) in total length, tail included, and can weigh over a kilogram (2.2 pounds). Coloring is variable but generally forms a banded pattern along the body. The feature that gives the species its name is its tongue, which ranges from blue-violet to cobalt blue. Like nearly all squamates — the group that includes lizards and snakes — blue-tongued skinks use the tip of the tongue to pick up microscopic scent molecules from the air and surfaces, then deliver them to a sensory organ in the roof of the mouth that provides their sense of smell. The tongue is also coated in a sticky mucus and doubles as a tool for catching prey, drawing tagged insects back into the mouth. Between its distinctive blue tongue and its curious temperament, the species has become a popular companion animal in Western countries.

Coloration varies widely by subspecies and region, and the species has a number of locally established color variations. Eastern blue-tongues show green and yellow phases, may or may not have eye bands, and even look different depending on whether they come from around Brisbane. Northern blue-tongues range from a classic, standard look to a more speckled pattern in populations from the Kimberley region and Prince Regent National Park. In captivity, breeders have produced albino, mostly white, and melanistic, mostly black, varieties, and herpetology hobbyists have bred captive lines with more exaggerated colors still, including red, yellow, orange, caramel, and white morphs. Tanimbar blue-tongues tend to be the glossiest, often appearing in gold or silver phases, and both the Tanimbar and Kimberley Northern populations have a reputation for being more aggressive in the wild than other blue-tongued skinks.

Behavior and diet

Blue-tongued skinks are diurnal, active during the day and sleeping at night. They are omnivorous generalists, feeding on insects, snails, frogs, other reptiles, small birds, small mammals, carrion, and plant material including fruit and green vegetation — they will even eat cane toads, despite the toads' toxicity to most native predators. The species is adaptable, often finding habitat in urban and suburban settings, including residential parts of Sydney, where it's generally welcomed as a beneficial resident because it preys on garden pests like slugs and snails.

When a blue-tongued skink feels threatened, its response is not to flee but to stand its ground: it may hiss, lunge, inflate its body, and flash its blue tongue in an effort to startle whatever it perceives as a threat — a defensive bluff rather than an attack.

Reproduction in the species is ovoviviparous — females retain fertilized eggs internally and give birth to live young rather than laying a clutch of eggs. Litter size ranges from 5 to 25 live young, with the eastern subspecies, Tiliqua scincoides scincoides, known for carrying the largest litters. The species is long-lived for a lizard, with documented lifespans exceeding 30 years.

Range and habitat

Tiliqua scincoides is native to Australia, with an additional population on Tanimbar Island in Indonesia's Maluku Province. Within that range, the species is notably adaptable, tolerating a wide variety of environments rather than depending on a narrow habitat type. It is regularly found in urban and suburban settings, including residential neighborhoods of Sydney, where its diet of garden pests makes it a generally welcome presence rather than a nuisance.

Conservation status

The blue-tongued skink is listed as Least Concern by the IUCN. It is an adaptable animal, often finding habitat in urban and suburban areas, including residential Sydney, where it is generally considered a beneficial dweller because it eats garden pests such as slugs and snails.