Unexpected Encounters with Australian Reptiles #3 - The Thorny Devil (Moloch horridus)

The Thorny Devil (Moloch horridus) is a native Australian lizard. It is also known as the Thorny Dragon, Mountain Devil, Thorny Lizard, or the Moloch and is the sole species of genus Moloch. The lizard was named by the botanist Dr. John Grey who derived the lizard’s scientific name, Moloch horridus, from Milton’s poem Paradise Lost. In the poem the Canaanite god Moloch is described as a “horrid king besmeared with blood of human sacrifice”.


The TD can grow up to 20 cm in length and can live up to 20 years. Coloured in camouflaging shades of desert browns and tans, these change from pale colours when warm to darker colours when cold. The species is entirely covered with conical spines that are mostly uncalcified (having a non-bony internal structure). It also features a spiny "false-head" on the back of the neck, the animal presents this to a potential predator by dipping its real head. Females are larger than males. The Thorny Devil's body is ridged in structure, and enables the animal to collect water from any part of its body, which is then channeled by capillary action to the lizards mouth.








An intimidating array of spikes cover the entire upper side of the body; these thorny scales are a defense mechanism against predators. Camouflage and deception may also be used to evade predation. It has an unusual gait, involving freezing and rocking, as it slowly moves in search of its preferred diet.


The thorny devil is found throughout the arid regions of Western Australia, the Northern Territory, south-western Queensland and western South Australia, living in sand, spinifex grasslands and scrub. The thorny devil starts breeding at three years of age. Like other dragon lizards it attracts a mate with elaborate courtship rituals, including leg-waving and head-bobbing! In November and December the female lays a clutch of 3–10 eggs in a chamber burrowed up to 30 cm below the surface. Incubation depends on weather conditions, with warmer temperatures reducing hatching time from 18 weeks to about 13 weeks. Once hatched, the young lizards start eating ants almost immediately. Oblivious to the ants’ bites, they lie on an ant trail or nest and may lick up 1,000 ants in a single meal and preferably one particular kind of ant, a small black ant called Iridomyrmex flavipes (Although they do eat a few other ant species as well, if they can't find any Iridomyrmex.)


Despite its looks and spines the thorny devil often falls prey to other animals, mainly bustards and goannas. Goannas also find and dig up the eggs of the thorny devils. And then there are the feral cats.








(Info sourced from various locations and the WWW)