Meet the Ridge-tailed monitor
The ridge-tailed monitor, better known to keepers as the ackie, is a small, powerfully built goanna of rocky northern Australia. It is chocolate brown with bright yellow or cream rings and spots, and its long tail is armed with rows of spiny scales.
Ackies shelter in rock crevices and burrows, where the air stays more humid than the surrounding desert. When threatened, they can block the entrance with their spiny tail, which can be swung like a club.
They are active, intensive foragers that eat mostly grasshoppers, beetles, spiders and other invertebrates, with small lizards and mammals making up a smaller part of the diet. Remarkably, about 70 per cent of their water needs come from their food.
George Albert Boulenger described the species in 1885. The species name acanthurus means 'spiny tail'. Several subspecies are recognised, and keepers know the forms as 'red ackies' and 'yellow ackies'.
Where it lives
Arid and tropical northern Australia, including northern Western Australia, the Northern Territory and north-west Queensland, with island populations on Groote Eylandt and the Wessel Islands. Lives in rocky ranges and outcrops.