Why seals don't drown

Seals are every diver's dream. They possess a marine endurance that few mammals can match; they never drown, they can hold their breath for 10 to 90 minutes, depending on the species; they can dive for hours, one after the other, with almost no rest. But where does this extraordinary endurance of seals come from? What are the natural secrets that make them so special in the water? And what can we learn from them?

Seals do not drown thanks to a combination of physiological and behavioral adaptations that allow them to live in water without problems:

• Controlled breathing. Seals breathe air like us, but they can hold their breath for very long periods when diving underwater. This is possible because they have a large lung capacity and specialized muscles that reduce oxygen consumption during diving. They can stay underwater, depending on the species, for 10 to 90 minutes at a time, and can even perform consecutive dives for hours without significant breaks.
• Oxygen distribution. Much of the seals' oxygen is not only in their lungs, but also in their muscles, bound to a protein called myoglobin, which acts as an oxygen reserve. This allows seals to continue moving underwater without breathing. Furthermore, seals have more blood in proportion to their body. The end result of these factors is that they always have a large oxygen supply.
• Slowing of the heartbeat. When they dive, seals dramatically reduce their heart rate (a phenomenon called diving bradycardia), so they consume less oxygen and conserve it to protect their vital organs, especially the brain and heart. Seals' hearts slow to less than half their normal rate when they are underwater.
• Closure of the airways. Seals have natural valves in their airways that automatically close underwater, preventing water from entering their lungs. And they can hold their breath much better than humans.
• Adaptive behavior. Finally, seals always know where the surface is and surface when they need air. There's no risk of "forgetting to breathe," as can happen to humans who tire or fall asleep underwater.
• Pressure resistance. Seals also dive at hundreds of meters deepTheir bodies are elastic, their lungs and airways compress without collapsing, reducing the risk of pressure-related injuries. Humans, without equipment, can get within a few meters before the pressure becomes dangerous.

By studying seals, it's been possible to glean a series of useful insights that are also valid for humans when they go underwater: from breathing techniques to brain protection, from the ability to manage the body and make it adaptable to any condition, even extreme ones, to the ability to avoid wasting energy, which in this case means oxygen first and foremost. Thanks to these incredible abilities, seals are also indicators of the health of the oceans: if they suffer, it often means that theecosystem he's in trouble.

Read also:

• How fish move in water
• Why sharks need to be protected
• Whales most at risk of extinction