There are some amazing looking lizards out there. There are striped and spotted lizards, colourful lizards, lizards with funny eyes and feet, and there are lizards with lovely spines growing out of them. Today’s animal has to be a winner in that last category, for the thorny devil is one of the spikiest lizards I’ve even seen. These lizards are so weird that they are placed in their own genus, Moloch.
Thorny devils (also known as thorny dragons, or molochs) live in Australia, in the Great Sandy Desert. They prefer sandy areas, and are generally not found in areas with rocky or hard soils. Thorny devils dig burrows to stay in during the hottest months of the year, which is why they like places with diggable sand. Burrows are about ten centimetres underground, and generally measure 5x5x12cm.
These lizards don’t grow to be super large, reaching maximum lengths of eleven centimetres. Female thorny devils are larger than males, weighing up to 88.7 g, while males only get up to weights to 49 g or less. Thorny devils are known for their spines, which cover their entire bodies. The spines are hard, but are not supported by any bone structure. The lizards are coloured perfectly in shades of gold and brown to blend in with their desert habitat; they are notoriously difficult to find.
You’ve probably guessed part of the reason thorny devils are covered in all those spines. They are not particularly fast, moving in a slow, jerky fashion. So the spines help these lizards avoid predation, because who would want to swallow a one? I can’t imagine that it would be very pleasant. Thorny devils have another defence, besides from camouflage and large, sharp spines. They have a false head on their backs, which they can present to predators when threatened. They tuck their true heads between their legs, presenting the false head and making themselves even harder to swallow. It’s a brave predator that chooses a thorny devil as its meal.
So the spines are great for self defence, but they also serve a second, very important purpose. Between each of the spines are small grooves, which serve as channels to direct water into the lizards’ mouths. When water condensates onto a thorny devil’s body, it moves into the grooves and is then channeled into the lucky lizard’s mouth via capillary action. This process works even against gravity, such as moving up the lizard’s legs. For a desert animal, this a very important adaptation.
Thorny devils subsist on ants, eating large numbers of the small insects every day to meet their nutritional needs. They munch on around 750 ants per day, though this number can rise into the thousands. I know ants are pretty small, but the large quantities do add up, so thorny devils have special large stomachs to accommodate such numbers. As they are slow moving, thorny devils don’t actively hunt ants. Instead, they wait under cover near ant trails, and scoop up the bugs as they crawl by.
Mating season in thorny devils occurs from August to December, in winter and spring. Males approach females and bob their heads by way of greeting, and then hop on and hope the females are receptive. If they aren’t, the females fall down and roll over, tossing the males off. If all goes well, the pair mates and the females leave to lay their eggs.
Three to ten eggs are laid in a special burrow dug by the female. She then carefully covers up the burrow to hide all evidence of her presence. The eggs are incubated for 90 to 132 days. After hatching, the young consume their egg casings before leaving the burrow and starting out on their own.
Thorny devils are some of the coolest lizards I’ve seen! I’m a little envious of all their spikes.
Cover image by Stu’s Images, CC BY-SA 4.0, via Wikimedia Commons
Our Wild World 
