This massive goanna, which attains a length in excess of two meters and may weigh as much as ten kilograms, is a predator that will eat anything it can capture. Its prey consists of snakes, lizards, ground-dwelling birds, mammals, and even small kangaroos. Rabbits, caught in their burrows, now comprise a major part of its diet, making this large monitor a most beneficial species.

The Perentie inhabits desert and semi-arid regions, and is found in all mainland States of Australia, except Victoria. It lives in burrows or beneath rocks.

Generally the Perentie, despite its large size, will try to avoid danger by running, heading for a tree where, well above the ground, it sits frozen still, and with its color pattern disrupting the body outline, can easily be mistaken for a branch. The big Australian monitors never attack humans, but if cornered and threatened will defend themselves. For this they are well equipped, having massive claws and powerful jaws, while the lashing of the heavy tail also can cause considerable damage.