The Thorny Devil comes in all shapes and sizes and there are some quite bizarre ones. It is distinguished by its long, curved spines, attractively dappled with yellow, orange, brown and white markings.

Despite its very spiky appearance it is tiny and quite harmless.

The scientific name was derived from a poem by Milton which described the Canaanite god Moloch, a 'horrid king besmeared with blood of human sacrifice.' However, the ferocioous appearance of the Thorney Devil belies it nature - this lizard feeds only on small black ants. They will sit by an ant trail simply eating them as they run past.

They will consume several species of ants, but are especially partial to very small Iridomyrmex ants, especially Iridomyrmex flavipes . Feeding rates have been estimated at from 24 to 45 ants per minute. Occasional objects such as small stones, sticks, tiny flowers and small insect eggs are also ingested -- these are probably objects being carried by ants and are eaten only accidentally. Large numbers of ants are eaten per meal by an individual thorny devil (estimates range from 675 to 1000-1500 to 2500).

There is a large bump behind the neck and an extra large, curved spine above each eye, which further accentuates its blunt snout. This lizard averages nine centimeters in length. The purpose of the large bump is unclear but since it lowers its head when frightened, present the spiky hump to the would-be predator possibly acts as a defence mechanism. When disturbed, Thorny Devils will also inflate themselves with air, puffing up like little puffer fish.

They have an almost mechanical jerky gait and they often freeze in place while walking, frequently with a foot off the ground. This probably helps to conceal a lizard caught out in the open. They can also change color rapidly -- when warm and active, they are usually a pale yellow and red, but when alarmed or when they are cold, they are dark olive drab.

Despite their camouflage and thorny spines, Thorny Devils are not immune to predation. Australian aborigines and bustards, both visual predators, have been observed to prey upon thorny devils.

They are able to drink by taking up water along capillary grooves on the skin that lead the water to the mouth. In this way they maximise water uptake from light showers or even dew.

They are found throughout the arid sandy regions of Western Australia, the Northern Territory, south-western Queensland and western South Australia. They are often seen on the sandy tracks that traverse Francois Peron National Park. Thorny Devils are found in two quite different habitats: spinifex-sandplain and sandridge deserts of the interior and the mallee belt of southern South Australia and southwestern Western Australia. The geographic distribution of thorny devils corresponds more closely to the distribution of sandy and sandy loam soils than to any climatological field.

These slow-moving, placid lizards rely mainly on camouflage and their unnpalatable spines for their defense. They are seen most often in spring, when they search widely for mates. Males engage in combat, head butting other suitors to gain access to the female.

Three to ten eggs are laid in late spring or early summer in a shallow, slanting burrow.

References:

Thomson, Carolyn, Animals of Shark Bay, Dept of Conservation and Land Management (AU)

Swan, Gerry, A Photographic guide to Snakes and Other Reptiles of Australia, The Austrlaian Museum and New Holland Publishers, 1995

Swan, Gerry, Green Guide: Snakes & Other Reptiles of Australia, New Holland Publishers, 1998.

Australia's Thorny Devil - http://uts.cc.utexas.edu/~varanus/moloch.html