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
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).
Latest Answers