How Can Seals Hold Their Breath for an Hour or More?
[html]Humans can't sense their own oxygen levels, but seals can, and it makes diving longer and safer.[/html]
Source: How Can Seals Hold Their Breath for an Hour or More? (http://ht**://www.discovermagazine.c**/planet-earth/how-can-seals-hold-their-breath-for-an-hour-or-more)