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I was wondering, why can't humans live under water like whales or seals? If whales can live underwater, and they're mammals, why can't we?

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closed as off-topic by David, terdon, Bryan Krause, Charles, Amory Jan 3 '18 at 14:04

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  • $\begingroup$ Looking for an expert! $\endgroup$ – jackthedog Nov 29 '17 at 16:21
  • $\begingroup$ Seals and whales can't live under water indefinitely, they have to come up to breathe. Just as humans can spend a couple of minutes under water, but have to come up to breathe. Seals and whales have just evolved mechanisms that allow them to hold their breath longer. (And others to minimize heat loss, wrinkly skin, &c.) $\endgroup$ – jamesqf Nov 29 '17 at 19:34
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    $\begingroup$ @jackthedog Is there any reason why your question is specific to humans and not to tigers, rats, antelope or other mammals? $\endgroup$ – Remi.b Nov 29 '17 at 20:17
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Kooyman et al. (1981) Annu Rev Physiol 43: 343-356; emphasis mine:

What explanation can we offer for the known capability of some marine mammals, such as Weddell seals and sperm whales, to remain submerged for over an hour?

(a) a large total oxygen store relative to body size, and

(b) parsimonious use of blood oxygen due to the lowered energy requirements of various organs.

During long dives, some organs deplete their oxygen stores, become predominately dependent on anaerobic metabolism, and build up large quantities of lactate. The result is a degree of fatigue that leaves the animal incapable of further intense diving activities for some time.


https://www.ncbi.nlm.nih.gov/pubmed/7011189

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