Whales, dolphins, and porpoises all belong to the same taxonomic order called cetaceans. Cetaceans are comprised of about 80 kinds of whales, dolphins, and porpoises. The word cetacean is derived from the Latin "cetus" (a large sea animal) and the Greek "ketos" (sea monster). Cetaceans use a magnificent way of communicating using ultrasound.
Porpoise species include the Harbour porpoise, Gulf of California porpoise. The dorsal fin on a porpoises is triangular in shape unlike the hooked dorsal fin of dolphins. Porpoises grow up to 7 feet (2.1 meters)