Soil water harvest inspired by desert horned lizards

Desert-dwelling creatures have evolved ingenious water ingestion mechanisms for survival. Among them, desert horned lizards use a dermal drinking method, wherein integumental microchannels on their skin draw water from raindrops or wet soils via capillarity. However, the mechanism by which they effectively drink the water accumulated between their jaws after capillary transportation from their skin remains elusive. Here, we investigate the drinking mechanism of the desert horned lizard, Phrynosoma platyhinos. Our visualization of water drinking in the lizard reveals that jaw-opening collects water into the jaw corner, which is then squeezed into the mouth when the jaw closes. For a quantitative analysis, we used two parallel plates fixed on one side as a model system of the lizard’s mouth and examined the flow near a corner with respect to opening angle, unveiling that the observed characteristic jaw motions facilitate the fast water uptake. Our findings inspire us to design a novel water-harvesting system that mimics the lizard's periodic jaw motions to collect soil water, offering a potential solution for water scarcity in harsh environments. Furthermore, the integration of ion-exchange membranes and porous media suggests a dual functionality of simultaneous water collection and purification, demonstrating potential applications in desalination and heavy metal removal.