The famous image of a spout of water rising as a whale surfaces leads many to believe whales are expelling water into the air. But whales don’t have water in their lungs.
Contrary to popular belief, whales cannot breathe underwater. They can hold their breath for an astonishingly long period of time, remaining underwater for up to 90 minutes. But like any other mammal, they need to breathe air. Whales have blowholes on their heads which work like nostrils; the spray is just them exhaling air.
So what makes the spray? Some of it may be water on the top of the whale’s head when it surfaces, and some is mucus, just like when you blow your nose. But the rest of the spray is actually water vapour. The air inside a whale’s lungs is much warmer than the air outside. When this warm air is expelled, it immediately condenses into water vapour.
Whales are mostly very docile and social mammals, but they can be intimidating due to their size. It may come as a surprise that not all whales have teeth. Some have a comb-like fringe in their mouths which helps to filter through their food. Some of the biggest whales feed on the smallest of fish.