Featured Creature: Thorny Devil

thorn-devil

The thorny devil (Moloch horridus) looks like something straight out of an old Japanese monster film. Thankfully, the lizard only averages eight inches (20 centimeters) long and spends most of its time terrorizing ants, not denizens of Tokyo.

thorny devil in road

The first part of the devil’s scientific name–Morloch–comes from a Canaanite god who demanded the sacrifice of children. The second part–horridus–means “horrible or causing horror.” Apparently John Gray, the zoologist who named the lizard, wasn’t a fan.

morloch

The thorny devil lives in the arid inland deserts of Australia which average less than 10 inches of rain for the entire year. To make the most of any available moisture, the lizard has evolved a network of grooves in its skin that channel water towards the corners of its mouth. These grooves are so narrow that the water is pulled along solely by capillary action, allowing the devil to harvest water from even the scantest morning dew.

thorny-devil-flipped

The curious knob on the thorny devil’s neck is actually a “false head” meant to deceive predators. When a devil feels threatened it will curl its real head between its front legs, leaving the false one exposed to attack.

thorny-devil-knob

The thorny devil specializes in eating ants, particularly ants of the genus Iridomyrmex–commonly known as “meat ants”. However, because ants aren’t particularly nutritious scientists estimate devils eat anywhere from 600 to 2500 per meal. Undigested ant bits, pieces of hard exoskeleton, give the lizard’s fecal pellets their distinctive black and glossy look.

meat-eater-ant-feeding-on-honey

You might have noticed that thorny devils bare some resemblance to the horned lizards found in the U.S and Mexico. Like the thorny devil, horned lizards are slow-moving ant eaters. However, the species are only distantly related. Their outward similarity is due to convergent evolution–the tendency for species to develop similar characteristics when they occupy the same ecological niche. The “horns” of the horned lizard are composed of bone, while the thorny devil’s spikes are made of keratin, the same material found in hair and fingernails.

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heads_graphic

References:

Pianka, Eric R. “Australia’s Thorny Devil”. Accessed July 31, 2014. http://uts.cc.utexas.edu/~varanus/moloch.html

“Moloch horridus – Thorny Devil, Mountain Devil”. Animal Diversity Web. Accessed July 21, 2014. http://animaldiversity.ummz.umich.edu/accounts/Moloch_horridus/

Australian Bureau of Statistics. Year Book Australia, 2006. http://www.abs.gov.au/ausstats/abs@.nsf/…

Photo credits:

Thorny devil close up – Jurgen Otto

Thorny devil on road – Steve Shattuck

Morloch – Internet Archive Book Images

Thorny devil in desert – Derek A. Young

Thorny devil’s false head – Courtesy of Cowyeow

Horned lizard – Pat Gains

Ant – Fir0002

Heads graphic – Digimorph

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