Introduction to Marine Biology 3rd Edition by George Karleskint, Richard Turner, James Small

Exercise 5

M any marine mammals have evolved a variety of physiological mechanism that allow them to dive to great depths and stay submerged for long periods of time. These include shunting blood during a dive from less vital organs to the brain and heart, muscles that store more oxygen and are less sensitive to lactic acid, a brain stem that is less sensitive to carbon dioxide, and a more red blood cells than terrestrial animals.