Cetaceans is a collective term for whales, dolphins and porpoises. The name is derived from the scientific (Latin) name of these animals: Cetacea.
What is the difference between dolphins and porpoises? Dolphins and porpoises belong to different whale families. The most obvious differences are: dolphins have a falcate (hook-shaped) dorsal fin, whereas porpoises have a triangular dorsal fin. dolphins have conical teeth; the teeth of of porpoises are spatula shaped. most dolphin species have a distinct beak. Porpoises don't, giving their head a more rounded, blunt shape.
Keep in mind that in the US it is illegal to directly approach dolphins.
Some dolphin names (species): Tucuxi (Sotalia fluviatilis) - 1.3 to 1.8 m Hector's dolphin (Cephalorhynchus hectori) - 1.2 to 1.5 m Black dolphin (Cephalorhynchus eutropia) - 1.2 to 1.7 m Commerson's dolphin (Cephalorhynchus commersonii) - 1.3 to 1.7 m Vaquita (Phocoena sinus) - 1.2 to 1.5 m Finless porpoise (Neophocaena phocaenoides) - 1.2 to 1.9 m George 5 ft 6 in Henry 5 ft 10 in Joel Gondelman 5 ft 10 in