Blue-tongue lizards are big, very slow-moving and friendly skinks. But even if they’ve never seen humans before they are likely to just sit there and let you pick them up when you see one. However they prefer firm ground under their feet.
There are six species of blue-tongue lizards in Australia. They vary a bit in colour and size, but most commonly they are grey with broad brown stripes across their back and tail, and they grow to around 300mm in (body) length.
This one is an Eastern Blue-tongue Lizard (Tiliqua scincoides scincoides) and lives where I live in south-eastern Australia. It has a big head and long body with very short legs and small feet. The tail tapers evenly and is shorter than the body.
Males have a larger head than females who are bigger overall. Their most noticeable feature is the blue tongue inside the bright pink mouth. Like all reptiles they do not produce any body heat. Their body temperature depends on the surrounding temperature (30 to 35°C to be active) which is why I found mine basking on the hot concrete driveway. On cold days he remains inactive in my workshop/garden store.
Their diet consists of plant matter and small animals such as beetles, caterpillars, crickets, snails and even other small lizards. They are very partial to slow creatures like slugs and snails. Blue-tongue lizards have strong jaw muscles to crush big beetles and snail shells. They may also bite in defence when they feel threatened.
The blue tongue’s main defence strategy is bluff. It faces the threat and opens its mouth. The blue tongue inside the pink mouth is an unexpected and vivid sight, designed to frighten off the attacker. It also hisses loudly and flattens its body which makes it look wider and bigger. If you pick the lizard up now it will bite and hurt you. They have a habit of latching onto a finger and not letting go, leaving a painful bruise.
(most of these words were found here)