Underwater breathing refers to the ability to extract oxygen from water, a process primarily seen in aquatic animals like fish. They utilize specialized organs called gills to filter oxygen from the water as it flows over them. This adaptation allows them to live and thrive in aquatic environments without needing to surface for air. In contrast, humans and most land animals rely on lungs for breathing air. While some technologies, such as scuba gear, enable humans to breathe underwater temporarily, they do not allow for natural underwater breathing like that of marine life. Understanding these differences highlights the unique adaptations of various species to their environments.