Do sharks have to swim to breathe?
Some sharks must swim constantly to avoid suffocating, while others can breathe while lying still.
Sharks use two main breathing methods. 'Ram ventilation' requires species like the Great White to swim with their mouths open to push water over their gills. If they stop moving, they stop breathing. Other species, like Nurse sharks, use 'buccal pumping.' They use cheek muscles to pull water into their mouths, allowing them to rest on the ocean floor without moving.
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The biological distinction between shark breathing methods is rooted in evolutionary adaptation to specific niches. Obligate ram ventilators, such as the Great White (Carcharodon carcharias) and the Mako shark, lack the necessary muscles to pump water manually. Research conducted by the Florida Museum of Natural History indicates that these species must maintain a minimum forward velocity to ensure oxygenated water reaches their gill filaments.In contrast, bottom-dwelling species like the Nurse shark (Ginglymostoma cirratum) utilize buccal pumping. This process involves the contraction of oral muscles to actively 'gulp' water and force it through the respiratory system. This allows them to remain stationary for long periods, often hiding in crevices or on the sandy floor to conserve energy or ambush prey.For species that are obligate ram ventilators, sleep is a complex physiological challenge. A 1970s study on Spiny Dogfish sharks suggested that their spinal cord, rather than the brain, controls the swimming motion. This allows the shark to enter a restful state while the body continues to move automatically. Recent observations by marine biologists using underwater drones have confirmed that some sharks may also face into strong currents to achieve ventilation while remaining relatively still.
Verified Fact
FP-0004265 · Feb 18, 2026