How many species of cetaceans are there in the world? Have any of them disappeared?
Approximately 80 different species. Why approximately? Certain species have only been observed on rare occasions while descriptions of others are based on but a few bone fragments. Still others form the basis of ongoing debate over classification. For example, the common dolphin (Tursiops truncatus or flipper) could include several species or subspecies. Genetics should answer some of the more thorny questions on this subject. No modern-day species of cetacean has become extinct, however, several populations have disappeared.
