An oxbow lake is a crescent-shaped body of water formed when a meandering river changes its course. Over time, sediment builds up around a bend in the river, eventually cutting off that section of water. This creates a separate, still lake that resembles the shape of an oxbow, which is a yoke for oxen. These lakes are often found in floodplains and can support diverse ecosystems. As they age, oxbow lakes may fill with sediment and vegetation, eventually becoming marshes or wetlands. They play a crucial role in maintaining biodiversity and providing habitats for various species, including fish and birds.