Blowing bubbles can be surprisingly useful for groups of humpback whales. Just beneath the surface of the Pacific Ocean if one humpback whale swims round in circles and blows air through its blowhole it will make rings of bubbles. Deeper down, other whales chase swarms of fish into the middle of the ring of bubbles, stopping them from swimming away. When there is enough fish in the ring, one whale gives a noisy signal and they all swim up together, open their mouths wide, and eat.