One of Australia's most famous and charismatic animals is the thorny devil (Moloch horridus). It's famous because it looks cool, and because it's not all that easy to find. It's also the only member of the amphibolurine agamids that isn't referred to as a dragon. Although... dragon... devil... I can see a theme here.
I found my first thorny devil in 2005, when I was an 18-year-old backpacking around Australia. It was crouched down on the Barkly Highway as we were driving between Camooweal and the Northern Territory border. My travel companion - the owner and driver of the car - was getting annoyed at me because I kept yelling for him to stop for animals, and by the time we stopped the animal would be gone (this is a frequent problem when driving at 110 km/hr). I promised him that this time the animal would still be there, and thankfully he stopped. I was so overjoyed I even went to the trouble of taking a picture of it. Here it is:
I am not a photographer. There are better pictures coming.
Not that you can tell from that picture, but the thorny devil is a really weird, unique, beautiful lizard. Better views of thorny devils can be had by looking at Angus Kennedy's pictures from my 2012 field season. While Angus and Mitch were helping me catch dragons in the Northern Territory and South Australia we came across three thorny devils.
This is the standard thorny devil pose that appears in pretty much all books about Australian reptiles and wildlife. Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
The thorny devil lives in Australia's more foreboding habitat, the dry, arid interior, where water is a valuable commodity. Its scales are specially designed so that, when any part of the lizard comes in contact with water, that water is funnelled to its mouth through capillary action, the same process that gets water from the roots to the leaves of trees. This was such an incredible discovery that its original description was published in Nature, one of the most important scientific journals. Subsequently, it has been a continuing area of interest for biologists.
A thorny devil at the entrance to an ant's nest. Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
Other than the water-funnelling thing, there's not much known about thorny devils. A Google Scholar search for their scientific name turns up only thirty two results, many of which are observations of their basic natural history. They're famous for eating ants, and this paper has an adorable picture of one in "characteristic feeding posture" eating ants off the side of a tree. That so little is know about such a famous and charismatic animal is alarming; I can't even find population estimates for them.
Unlike most dragons, the thorny devil ambles slowly. Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
An additional theme I can see in the limited literature is that thorny devils are slow. In fact, in one of the most hilarious titles to a scientific paper I've ever seen, this article asks "is the devil a sloth?" Although we all know what the authors mean, and scientists are not without a sense of humour (well, most of us, anyway), sloths are, in fact, animals (mammals of the order Pilosa) and thorny devils are definitely not sloths.
Thorny devils have a weird protuberance coming out of the back of their neck. Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
There's a weird lump coming out the back of the thorny devil's neck. I've heard it said that this is a false head, and that if a thorny devil feels threatened it'll crouch down and stick up its false head for sacrifice to the predator. I can't find any evidence for this in the literature. It is true that, when threatened, the thorny devil will crouch down and arch it back, but this is standard posture for animals that have spiky backs: it presents the predator with their least palatable body part. This behaviour can be seen spike-backed creatures like porcupines, hedgehogs, echidnas, lion fish, armadillo lizards and those horrible spiky caterpillars that curl up in a ball when you touch them. Furthermore, at an extremely informal poll at last year's meeting of Australian herpetologists, I couldn't find anyone who's ever seen a thorny devil without that weird lump. Geckos and skinks, which wiggle their tails to fool predators, are frequently found without tails, and have even evolved a mechanism for automatically detaching their tails and growing new ones. Not that I'm saying the false-head explanation isn't true, but just that I haven't heard of any convincing evidence. If you know of any evidence for the use of the weird lump, I'd be curious to hear it.
Thorny devils are spectacularly coloured and patterned. Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
Thorny devils are a good example of disruptive colouration. Their colours are the same colours as arid Australia, and they are patterned in such a way that it's hard to make out the shape of the lizard, especially if it's against a complex background. Of course, in these pictures, where we've deliberately placed the lizard against the homogenous backdrop of a dirt road, and it's easy to see.
Thorny devils are the opposite of dolphins: they always look grumpy. Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
One paper, that I admit is not the most convincing, suggests another adaptation that thorny devils have to their arid home: they may pee on their eggs to keep the eggs moist.
Such a cool lizard! Thurlga Station, South Australia, 2012. Photo by Angus Kennedy.
I thought I'd end with a picture I found online. Thorny devils are quite dramatic looking, especially head-on, but I've never seen them look quite as terrifying as in this artificially-coloured image of a thorny devil skull overlayed onto an image of its head, taken from this website.
The thorny devil at its most terrifying, courtesy of digimorph.org.
