Cetaceans
Cetaceans, such as beluga whales and dolphins, blow bubble rings. Dolphins sometimes engage in complex play behaviours, creating bubble rings on purpose, seemingly for amusement. There are two main methods of bubble ring production: rapid puffing of a burst of air into the water and allowing it to rise to the surface, forming a ring; or swimming repeatedly in a circle and then stopping to inject air into the helical vortex currents thus formed. The dolphin will often then examine its creation visually and with sonar. They also appear to enjoy biting the vortex-rings they've created, so that they burst into many separate normal bubbles and then rise quickly to the surface.
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A bubble ring forms a vortex ring, shaped like a doughnut which spins poloidally in the direction of the arrows
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A underwater diver blows a bubble ring
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Beluga whales blowing bubble rings
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Aerial view of a humpback bubble net
Humpback whales use another type of bubble ring when they forage for fish. They surround a school of forage fish with a circular bubble net and herd them into a bait ball.
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