A shark can drown if insufficient oxygen is absorbed from the water as it passes through the shark's mouth and across the gills. Some species of sharks can continue to breathe without needing to swim constantly, while other shark species must continuously swim to avoid drowning.Continue Reading
Sharks use either buccal pumping, where muscles around the shark's mouth pull in water; or ram ventilation, where water is forced into the shark's mouth through forward motion.
Buccal pumping refers to the movement of the cheek muscles some sharks possess. For example, bottom-dwelling sharks, such as nurse sharks and carpet sharks, can replicate the effects of swimming by using buccal pumping to pump water over their gills - even when their body is completely still. Additionally, some species of sharks possess organs called spiracles that pump water over the gills through inlets behind the eyes. This reduces the need to swim and allows the shark to remain still to conserve energy and ambush prey.
Sharks that lack buccal - or cheek - muscles must continuously swim to avoid drowning. These sharks, such as the great white shark, hammerhead shark and reef sharks, use ram ventilation to breathe as they swim through the water.Learn more about Sharks