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The Thorny Devil Lizard’s Moisture-Extracting Skin

The Thorny Devil Lizard’s Moisture-Extracting Skin

THE Australian thorny devil lizard (Moloch horridus) extracts moisture from fog, humidity, and wet sand. Then it channels the water to its mouth for drinking. How? The answer may lie in the lizard’s amazing skin.

Grooves on the surface of the skin are connected to a network of channels below the skin so that water is directed to the sides of the thorny devil’s mouth

Consider: The thorny devil’s skin is overlaid with scales. Some scientists think that moisture or dew collected on the scales runs down to the rough surface of the skin and enters the skin’s network of half-open channels, or grooves, located between the scales. These channels are interconnected and lead to the sides of the thorny devil’s mouth.

But how does this lizard draw up water—up its legs, across its body, and into its mouth—defying gravity in the process? And how does the thorny devil extract moisture from wet surfaces by rubbing its belly against them?

Researchers have apparently unveiled the thorny devil’s secret. The channels on the surface of the skin are connected by way of ducts to another network of channels below, that is, within the lizard’s skin. The structure of these channels enables capillary action—a phenomenon in which water is drawn into narrow spaces even against the force of gravity. The lizard’s skin thus acts as a sponge.

Janine Benyus, president of the Biomimicry Institute, says that mimicking moisture-extracting technologies may help engineers design a system to remove humidity from air in order to cool buildings more efficiently and also to obtain drinking water.

What do you think? Did the moisture-extracting skin of the thorny devil come about by evolution? Or was it designed?