According to the Institute for Marine Mammal studies, dolphins can generally hold their breath for as long as 10 minutes. They normally breathe about four to five times per minute.
Unlike humans, dolphins are voluntary breathers. This means they must think about every breath that they take. Therefore, dolphins do not sleep in the same way as humans because due to the possibility of drowning; rather, they shut down half of their brain at a time to rest while the other half stays awake so that they can breathe. As a result, dolphins tend to take naps throughout the day.