The age-old question always sparks controversy. 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 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.
Porpoises have no sense of smell.
Test have determined the intelligence level of porpoises to be between that of a dog and that of the highest-known intellect in the nonhuman animal world, the chimpanzee. Historically, sailors have taken the presence of porpoises near their boats as a sign of good luck.