Dolphin

From Wikinfo

The term 'Dolphin' refers to a group of aquatic mammals, specifically whales of the Family Delphinidae, including the beaked the beaked dolphin, the killer whale, the pilot whale, and 12 freshwater species in South America and S Asia. (Expound upon this)

Dolphin Intelligence

The Dolphin Brain is similar in size to the human brain (slightly larger in some, up to 5 times larger in others, like the Orca, but their brain to body ratio is slightly lower than humans on average. Their brain consists of two hemispheres divided into four lobes�very different from the human brain. It is unknown why dolphins evolved this structure. Some hypothesize that the dolphin brain is shaped this way to allow for more acute conscious perception of three dimensions, thus allowing it to use its highly developed powers of echolocation. Others have gone as far as to say that dolphins perceive higher dimensions of reality than humans do. It appears that dolphins are an example of highly evolved oceanic intelligence. It has been long-theorised that they have a complex language, which may consist of visual symbols as interpretations of high frequency sound waves.