Dolphins have a blowhole on top of their heads and to breathe they must jump out of the water. They surface several times a minute to breathe. Lastly, dolphins are intelligent organisms. Their intelligence lies somewhere between that of dogs and chimpanzees. They have success in problem solving.
Common dolphins have the capacity for sustaining interests and fears.
They have moods as well as emotions which can both last for long periods of time. References Allen, Thomas B., ed. Wild Animals of North America. National Geographic Society, Washington D. C. Alpers, Antony. 1961. The Myth and the Mammal.