Dolphins are conscious breathers, which means they have to think about every time they want to take a breath. They respire through a nasal opening called the blowhole, which is located on the top of their head. When resting, their blowhole remains tightly shut. They are able to hold their breath for an average of 4-5 minutes and a maximum of about 10 minutes. Dolphins are efficient breathers. Dolphins are mammals, therefore they can't breathe underwater.
