Reptiles can live in arid environments due to special adaptations of their integument to such habitats. So called moisture-harvesting reptiles show behavioral and morphological adaptations, as their diet often does not cover the complete water demand and rain is scarce. The collection of water from various sources by moisture-harvesting reptiles is often accompanied by a stereotypical behavior: snakes coil up in the open and show a dorso-ventral flattening of their body to increase the surface area. Lizards also show a flattening of their body, but additionally raise their abdomen by splaying and extending their legs and lowering their head and tail. A similar behavior is observed in tortoises. Though there are several behavioral descriptions of moisture-harvesting reptiles, there are only few investigations about the physical principles enabling a passive collection of water. Special skin structures, comprising a micro structured surface with capillary channels in between imbricate overlapping scales, enable lizards to collect water efficiently. In some lizards, such as the Texas horned lizard Phrynosoma cornutum, water droplets applied to their body surface show a preferred spreading direction, transporting the water towards their mouth for ingestion. This passive directional transport is enabled by asymmetric and interconnected channels between the scales. Elucidation of the physical principles behind the directional water spreading has inspired a biomimetic transfer to optimize future applications in liquid handling, e.g. in fields of microfluidics.