Blue-Tongued Skink (Tiliqua scincoides)

Where do they live?: Eastern and northern Australia, and Irian Jaya in Indonesia

Habitat: Forests, grasslands, and gardens

Size: Head–tail length up to 24 in. (60 cm), males are longer and slimmer than females

Coloration: Gray, tan, or silver with dark bands; bright blue tongue

Diet: Berries, flowers, fruit, insects, and dead animals

Breeding: Up to 25 young born after a gestation period (pregnancy) of 110 days

Life Span: Up to 20 years

Status: Common

The blue-tongued skink is a large lizard that lives in a range of habitats in Australia, New Guinea, and various Indonesian islands. Some live in the desert or dry scrub, but many prefer the tropical forests. The legs and claws of the blue-tongued skink are not strong enough for it to dig its own burrows, so it shelters in the burrows of other animals, as well as in hollow logs, the spaces between rocks, and in leaf litter. When it moves through thick undergrowth, the blue-tongued skink folds its back legs out of the way and wriggles along like a snake. Blue-tongued skinks are active during the day, but they may retreat into their burrows during the hottest periods. During the dry season, when food and water are hard to find, large lizards save energy and moisture by staying in their burrows. They let their own body metabolism (normal body processes) slow down. The slow-moving blue-tongued skink cannot rely on speed to escape from predators. Instead, it puffs up its body, hisses loudly, and sticks out its bright blue tongue to scare them away.

Breeding Behavior

For most of the year, blue-tongued skinks live on their own. They come together to mate. Males usually start to look for a mate when it warms up in spring. The males fight for the right to mate, and many become seriously injured at this time. When a male finds a female who is ready to mate, he grips her neck or shoulder in his powerful jaws, and scratches her back with one of his back legs. After mating, males may sometimes guard females for up to twenty-five days.

Teeth and Feeding

Blue-tongued skinks are omnivores. This means that they feed on a wide range of animals and plants. They prey on animals that move more slowly than they do. Favorite foods include insects, fruit, flowers, leaves, fungi, snails, eggs, small vertebrates, and the remains of dead animals (carrion). The teeth at the front of the mouth are smaller than those farther back and are used to pick up insects and bite off pieces of plants. Snails and insects are crushed in the hard jaws before being swallowed. The strong jaws of the blue-tongued skink are also useful in defense, biting predators such as brown falcons, kookaburras, dingoes, monitor lizards, and snakes. Blue-tongued skinks were once thought to be poisonous. In the past, many were killed by people. But the fact is this lizard is not poisonous but can give a sharp bite to defend itself.

Mother and Babies

Four different species of bluetongued skinks give birth to live young instead of laying eggs. The number of young produced tends to increase with the size and age of the female. While young skinks develop inside their mother’s body, they are nourished by a body part similar to the placenta through which a human baby receives food from its mother.

Live Young

There are many advantages to producing live young instead of laying eggs. The female is less likely to be attacked and eaten by predators than the eggs would be. This gives the young a greater chance of survival. Blue-tongued skinks do not rely on speed to escape from predators or to catch food, so the pregnant females are not affected too much by the weight of the developing young inside them. The pregnant females bask in the sun because the warmth speeds up the development of their young. They tend to rest with their back legs and tail raised off the ground because of the size and number of young inside them. There are also disadvantages to giving birth to live young. If a pregnant blue-tongued skink is killed, all the young die with her. Basking increases the danger of attack by predators, as the bluetongued skink is out in the open, away from the safety of her burrow. Also it is not possible for a female to give birth to several lots of young lizards each year in the same way that many egg-laying lizards lay several clutches a year. In many parts of their range, female blue-tongued skinks may not breed every year, especially if there is a shortage of food.

Parental Care

After the baby skinks are born, they have to fend for themselves. The parents play no part in looking after their young. Young skinks take three years to develop into adults.