Native Australian Animals

The Mountain or Thorny Devil

The thorny devil, also known as the mountain devil, is native to Australia and is one of its most bizarre creatures. John Gray, who illustrated the animal in 1841, gave it the name Moloch horridus. Moloch was the name of a fierce Canaanite god while 'horridus' means bristly or rough. It is found throughout most of the arid regions of inland Australia

John Gould first exhibited the mountain devil in London in 1840. It is the only species in its genus and is anatomically somewhat similar to the North American horned lizards.

Although it looks so fearsome, it is harmless. It measures 10 to 150 cms in length. The mountain devil is rarely found in stony areas, preferring sandy soil. The climate of an area has less bearing on its distribution than does the type of soil. Vegetation in its habitat varies from mallee scrubland to Spinifex.

Thorny DevilCredit:

It meets its dietary requirements by eating huge numbers of ants. One ant at a time is flicked up with its sticky tongue. It is estimated that 45 a minute are eaten and between 600 and 3,000 at a time.

The mountain devil is easily identified by its prominent spines. These are soft and conical and completely cover the body, including above the eyes and on the legs and tail. A spiny appendage on the back of the neck acts as a false head if the animal is threatened. The head is tucked back between the front legs, leaving the knob-like protrusion to the fore.

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The mountain devil has a great disguise and can change colour rapidly depending on the surroundings. When warm and active they are a pale yellow, red and orange. When cold or alarmed they turn a dark olive.

The female is the larger and the stouter and can weigh up to 90 grams. In captivity, the life span is generally from 5 to 8 years. These creatures grow until their fifth year. Mountain devils hold their head and tail high, forming a banana-shape. They walk slowly and jerk and shake like a wind-up toy. Another defence against predators is to freeze, often with one leg off the ground. They sway as they stand and look like a dead leaf waving in the wind.

Mountain devils are diurnal. Mating and egg-laying take place from August through to December (late winter to early summer). During the hottest part of the day, they dig a shallow burrow or shelter under scrub or spinifex. It is a heliotherm and relies on the heat of the sun to raise its body temperature. Each morning it will sit in the sun until it is warm enough to go looking for food. Individual animals have special defecation sites.

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Breeding takes place during August and September. The female digs a nesting burrow using her hind legs to kick sand out of the way. She lays her 3 to 10 eggs in the burrow then fills it in and smooth the top leaving no trace of the burrow. The eggs sit in the air-filled chamber at the base of the burrow until they hatch three to four months later. The babies are replicas of their parents but only 63 to 65mm in length. Thorny devils grow until they are five years old but are mature at three.

Thorny devils get their moisture through thousands of tiny grooves all over the body. Any condensation or rain which falls on the animal is moved by a gulping mechanism through the grooves to the corners of the mouth. The thorny devil prefers to remain undetected. Should it be seen, the spiny surface acts as a visual deterrent. It will also puff itself up in an effort to appear larger. Many predators are sand goannas and raptors.