Water striders walk on water by trapping air in thousands of microscopic hairs on their legs.

Water striders belong to the family Gerridae and possess a remarkable evolutionary adaptation for aquatic life. Each leg is covered with approximately 12,000 microscopic hairs called microsetae, which feature even smaller nanogrooves that effectively trap air. This ingenious mechanism was detailed in a landmark 2004 study published in Nature by researchers from the Chinese Academy of Sciences.The trapped air creates a stable cushion between the leg and water surface, exploiting water's high surface tension of approximately 72 millinewtons per meter at room temperature. A hydrophobic wax coating on the legs prevents water from penetrating the hair layer, keeping the insect dry and unsinkable even in turbulent conditions.This physical system is remarkably strong: a single leg can support up to 15 times the insect's body weight without breaking the water's surface. Water striders can move at speeds exceeding 1.5 meters per second, using their middle legs as oars and their back legs for steering and stability during rapid maneuvers.This specialized anatomy makes water striders among nature's most efficient surface-dwelling predators. By distributing their weight across a wide area, they avoid disrupting the hydrogen bonds that hold water molecules together, creating the trampoline-like effect. Scientists are currently studying these microstructures to develop new waterproof materials and miniature aquatic robots.