Researchers at The University of Western Australia are part of a team which has investigated the remarkable drinking habits of Australia’s Thorny Devil lizard (Moloch horridus) – and it’s a fascinating insight into desert survival.
It’s already known that Thorny Devils can drink by standing in puddles and absorbing water through skin capillary channels between their overlapping scales that lead to their mouth. But researchers wanted to find out more about the other water sources the lizards might depend on, such as moist sand, morning dew and air humidity.
The story behind this research started with German PhD Student Philipp Comanns, from RWTH Aachen University in Germany, who contacted UWA’s Professor Phil Withers from the School of Animal Biology, an expert in the drinking methods of the Thorny Devil.
The research team set out to find if the Thorny Devil could extract water from various sources other than puddles. They measured this by weighing the lizard before and after exposing them to different water sources.
Their results confirmed that Thorny Devils could drink puddle water by absorbing it through the skin capillary tubes to its mouth. Each ‘mouthful’ of water was tiny, about a pinhead of water per gulp, squeezed out of the skin capillaries. But the scientists also made a further discovery – the lizards could absorb water by flicking moist sand onto their backs, as this helps them absorb water. Although not as efficient as standing in a puddle, moist sand was seen as an important source of moisture for the Thorny Devil.
The scientists then subjected the lizard to cooling of high humidity air. This ‘facilitated condensation’ proved unsuccessful – the Thorny Devil could not absorb enough water to be able to drink it.
The overall results found that rain and moist sand seem to be the most likely water sources for Moloch horridus on a regular basis.
Professor Withers said he had a real soft spot for the little desert survivor.
“Thorny devils are the coolest lizards to study – everything about them is special compared to other dragon lizards, from their special water drinking to their diet and how they feed, how they move, and their cryptic thorny appearance,” he said.
David Stacey (UWA Media Manager) (+61 8) 6488 3229 / (+61 4) 32 637 716