Question

What are blowholes?

Answer 1

Whales and dolphins are mammals and breathe air into their lungs, just like we do. They cannot breathe underwater like fish can as they do not have gills. They breathe through nostrils, located right on top of their heads.

Complete Answer:
To solve this question, we have to know about the blowhole. A blowhole is the hole (or spiracle) at the top of the head through which the animal breathes air. In baleen whales, these are in pairs. It is homologous with the nostrils of other mammals, and developed through gradual motion of the nostrils to the above of the head.
As whales come up for air, they forcefully exhale air via the blowhole. The exhaled air is free into the comparatively lower-pressure, cooler atmosphere, and any water vapor becomes liquefy. This spray is called the blow, and is usually shown from far away as a white splash that can also be happened by water remaining on top of the blowhole.
Air sacs just below the blowhole allow whales to produce sounds for communication and, for toothed whales, echolocation.

Note: When whales swim in the water then their nasal plugs block the nasal passage to the blowhole. The muscles maintaining the nasal plug are set free during this period, however when the whale comes above for air these muscles shrink and permit for the blowhole to be unblocked and the works for exhalation and inhalation to happen. Baleen whale has two blowholes located in a V-shape whilst a toothed whale has only a single blowhole.