http://dhr.dos.state.fl.us/symbols/porpoise.html Is it a porpoise or a dolphin? The age-old question always sparks controversy. Even the 1975 Florida Legislature, adopting the species as the official Saltwater Mammal, left the issue open, designating the "porpoise, also commonly known as the dolphin."
The porpoise, along with dolphin and the whale, all belong to the mammalian order Cetacea. Porpoise and dolphin are members of different families, but there is no sharp scientific distinction between them. The porpoise is generally smaller and does not possess the characteristic 3" bottle-nose of the dolphin. The playful porpoise is gray or black with a slightly lighter underside. It can live to the age of 30, occasionally attaining a length of 12', although most are in the 6'-8' range.