Whales and Dolphins: Not Fish, But Mammals
Because whales live in the ocean, many people think they are fish. But whales and dolphins are not fish. They are mammals — just like humans.
What Makes Them Mammals?
Mammals breathe air using lungs, give birth to live young instead of laying eggs, and feed their offspring with mother’s milk. All animals need oxygen, but fish extract it from water using gills, whereas mammals take oxygen from air with lungs. Whales and dolphins breathe air through their lungs as well.
Blowholes: Nature’s Breathing Apparatus
Whales and dolphins come to the ocean surface to breathe. Instead of noses like humans, they have a hole on top of their heads called a blowhole. When exhaling, they can produce a spray or mist called a spout, visible from miles away. Muscles around the blowhole keep it closed underwater and open at the surface.
One Blowhole or Two?
Some cetaceans have two blowholes, while others have only one. Pilot whales and dolphins have a single blowhole, whereas humpbacks, minkes, and right whales have two. Observing the blowhole can help you distinguish between different whale species.
