A Blowhole is the hole at the top of a cetacean's head through which they breath air. It is similar to the nostril of other mammals.


When cetaceans come to the surface of the water to breath, they will expel air through their blowhole which produces a spray, known as blow, and this is often visible from a distance.


Baleen whales have two blowholes positioned in a "V" shape, while toothed whales have a single blowhole.