Elephant Nose Fish     A lot of us take some comfort in the belief that humans have the biggest brains on Earth in ratio to body size. Well, skeptics and ichthyologists have long known this to be untrue. A group of fishes called mormyrids, or elephant nose fishes have relative brain sizes that are larger than humans. These fishes use weak electrical currents to communicate and navigate in murkey waters. The theory goes that such an extensive brain is needed to generate this current and interpret the signals and changing electromagnetic field of the fish's surroundings.