Ducks Make Their Own Water-Repellent Oil
Special glands above a duck’s tail release a clear oil that the bird spreads across every feather with its beak. This coating prevents water from soaking in, keeping the duck buoyant and warm. The oil also helps trap a thin layer of air next to the skin, acting like a built-in life jacket.
💡 Fun detail:
Without this personal oil, a duck would become waterlogged and sink, so every preening session is a survival routine.
Source: National Geographic