The only species in the genus Moloch, thorny devils are odd-looking lizards. They have long necks and grow up to 6 inches from tongue to tail tip. Large thorny spines cover their bodies, including their tails and bellies. A large conical spike sits over each eye; a smaller spike rests above each nostril. Thorny devils walk slowly, shakily, holding their tails straight up.
Thorny devils live in the scorching deserts and arid scrub of Australia. The Great Victorian Desert, Great Sandy Desert, Little Sandy Desert, Tanami Desert, Simpson Desert, Gibson Desert and Tirari Desert are all habitats of the thorny devil. Australia's desert temperatures climb up to 122 degrees Fahrenheit and can fall into the 30s at night. Thorny devils tunnel under scrub shade to stay cool on hot days and cover themselves with dirt on cool nights.
The thorny devil's diet consists entirely of ants. The genus Iridomyrmex is a favorite meal. They also favor the genus Crematogaster. The many species of these two genera are found throughout Australia's deserts. The thorny devil stands above or beside the entrance to an ant chamber and slurps up the ants as they are streaming in and out of their tunnel. Adult thorny devils consume thousands of ants per day.
Thorny devils are not aggressive or territorial. These mild-mannered lizards are not a danger except to ants. Humans and bustards, a type of large bird, are the thorny devil's main predators. Thorny devils puff up to appear larger when threatened. Camouflage and the ability to remain motionless are their most effective defense mechanisms. The thorny devil hides under shrubs, tucking his head between his front legs, exposing a spiny hump that resembles a false head.
The female thorny devil will roll sideways and throw the male off her back if she is not receptive to breeding, but after successful copulation the female digs a tunnel 12 to 24 inches long at a depth of 12 inches, taking three or four days to dig it. She uses both legs on one side of her body to dig, switching sides periodically. Female thorny devils lose up to 40 percent of their body weight during this labor.
Emergence of Hatchlings
The female thorny devil lays one clutch per year between September and December, up to 10 of them in an orange-size chamber at the end of the tunnel. Incubation takes three to four months. Hatchlings dig a different tunnel to exit the egg chamber, all emerging from the same hole. They are less than 3 inches long. They live independently after emerging from the chamber.