A blowhole is a natural opening found on the tops of some marine mammals, such as whales and dolphins. It serves as a respiratory system, allowing these animals to breathe air while swimming. When they surface, they expel air and water vapor through the blowhole, creating a visible spout. Blowholes are typically located on the top of the head, which helps the animals breathe without fully emerging from the water. The size and shape of a blowhole can vary among species, influencing the height and direction of the spout produced when they exhale.