Seals can hold their breath for well over an hour, even baby seals already outperform the human world record, how come that’s the case?
In: Biology
Certain mammals can stay underwater longer than humans due to physiological adaptations that optimize oxygen storage and usage. They have higher concentrations of myoglobin in their muscles, larger blood volumes, and greater oxygen-carrying capacity, enabling efficient oxygen use. These animals can slow their heart rate (bradycardia) to reduce oxygen consumption and redirect blood to vital organs. Additionally, their flexible lungs and rib cages help withstand pressure and reduce nitrogen absorption, while anaerobic metabolism and large spleens provide extra oxygen reserves. Behavioral adaptations, such as gliding to conserve energy, also contribute to their ability to stay submerged for extended periods.
there are many factors at play here.
first of all they are breathing the same air as we do so in order to last longer with the same amount of oxygen they need to use less oxygen overall.
this is usually done by simply being optimized to move under water with less resistance so they need to use less energy which means less oxygen is being used.
beside this we could also stay under water for longer than we usually do, in fact when we breath out theres still oxygen left in the air even after holding our breath for a while.
the reason why we need to breath out and get a fresh breath of air is because we needs to get rid of the CO2 thats building up in our body.
So if you are a mammal thats not as sensitive to CO2 building up you can fully utilize the oxygen you breath.
but the biggest factor by far will simply be using less oxygen.
The true ELI5, which doesn’t actually *explain* anything, is: Because their bodies are adapted for doing so, and ours are not.
The proper explanation is that these creatures have significantly different circulatory and muscle systems which prioritize oxygen efficiency extremely highly. Their blood has far more hemoglobin in it than ours does, and they have differently sized (and possibly shaped) blood cells, allowing their cells to bind more oxygen than ours do. Their breathing habits are different, allowing them to take in far more oxygen than we can, and avoiding some of the issues of hyperventilating while they get ready for a long dive. Their muscles also contain extremely high concentrations of myoglobin, allowing the muscles themselves to store up oxygen for the dive. Their heart rates slow and send more blood to the brain and organs and less blood to the extremities.
In simple terms, their whole body is optimized for diving, at the expense of other things they could be doing. Humans are endurance hunters on dry land (usually rolling savannah or light woodland) or shallow water, so the proto-humans who did well in that environment are the ones who survived and had kids, meaning we slowly optimized for that, which is the long way of saying “we evolved like this.” Our adaptations make us more flexible but dependent on a continuous oxygen supply. Their adaptations make them extremely good at diving and kinda sucky at a bunch of things they almost never do anyway (like running for long distances on land).
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