Scientists have discovered that thorny devils are able to absorb water through moist sand
The thorny devil may not have to look far for a drink as they travel through the hot Australian deserts.
It was 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 have determined that rain and moist sand are the most likely water source on a regular basis.
A research team led by Philipp Comanns, a Ph.D. student from RWTH Aachen University in Germany and Phil Withers a professor from the University of Western Australia’s School of Animal Biology, concluded that these lizards can absorb water by flicking moist sand onto their backs, an important source of water as they travel through the hot Australian landscape.
“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,” Withers said in a statement.
The research team measured how the thorny devil could extract water from various sources other than puddles by weighing the lizard before and after exposing them to different water sources.
The results confirmed exactly how the lizard absorbs water through skin capillary tubes to its mouth.
According to an article in the Journal of Experimental Biology, Comanns discovered that the 40 g thorny lizards could absorb as much as 1.32 g of water during a one hour drinking session with an additional 1.28 g of water drank through their mouths.
Since this article was originally posted in 2016, researchers have expanded our understanding of the thorny devil’s moisture-harvesting abilities. In addition to confirming that these lizards can absorb water through skin capillary channels when standing in puddles, newer studies (2016–2018) reveal that moist sand is an equally critical water source. Using micro-CT scans and biomechanical analyses, scientists discovered that thorny devils employ specialized “sand-shoveling” behavior—flicking damp sand onto their backs—which helps saturate the network of capillary channels between their scales. These channels have a dual-scale, hierarchical architecture that enables rapid radial water transport toward the mouth, allowing thorny devils to take in water from sources as shallow as 3 mm puddles or from sand with about 22% moisture content.
In addition, experiments show that while condensation alone provides minimal hydration, it can “prime” the superhydrophilic skin for more efficient absorption when the lizard next encounters wetter substrates. Field observations confirm that thorny devils rely on repetitive bouts of sand-shoveling after rainfall to exploit otherwise fleeting moisture in their arid environment. This multi-pronged strategy—integrating specialized skin structures, behavioral adaptations, and environmental opportunism—further highlights the survival toolkit of *Moloch horridus* in Australia’s harsh deserts.
The lizard’s hierarchical channel architecture has inspired designs for atmospheric water harvesters that mimic sub-capillary structures could enhance fog nets. Microfluidic devices are another area that has benefitted from the inspiration. Researchers have explored directional transport without pumps has applications in lab-on-a-chip systems. For more, see The Fountain and the Royal Society.
