Baby Seal

Pinnipeds can hold their breath for nearly two hours underwater by conserving oxygen. When the animal starts diving its heart rate slows to about one-tenth of its normal rate. The arteries squeeze shut and the sense organs and nervous system are the only organs that receive normal blood flow. Pinnipeds are able to resist more pain and fatigue caused by lactic acid accumulation than other mammals. However, once they return to the surface, they need time to recover and normalize their body chemistry.
Ecology