> Date: Sun, 15 Mar 1998 01:07:22 -0800 > From: Julie Meissner <firstname.lastname@example.org> > To: aRomero@ACC.FAU.EDU, email@example.com > Subject: dolphins and whalse > > Dr. Romero; > > I am a teacher who is currently teaching a unit on the ocean to my > 2nd grade class. We have been studying whales and are about to begin > studying dolphins. In my research, I have come across the statement > that all dolphins are whales, but not all whales are dolphins. Could > you please explain why this is true from a scientific standpoint? All > that I have found seems to point to an evolutionary standpoint. What > specific qualities make dolphins considered to be whales, but whales not > to be considered as dolphins? > > Thanks for your help; > > Julie Meissner > > firstname.lastname@example.org > 2nd grade teacher > Turtle Bay School > Redding, California Dear Julie: The whole problem is that the word "whale" is a common name not a scientific one and is applied to species that are not necesarilly closely related. All whales, dolphins, and porpoises are grouped within the order Cetacea. Cetaceans are, in turn, divided into two suborders: mysticetes and odontocetes. The first ones are the baleen whales; they include the blue, fin, right, bowhead, gray, minke, sei, Bryde's, and humpback. They are also sometimes called "true whales." The other suborder, odontocetes, are composed by toothed cetaceans, that is dolphins, porpoises and many other species that also receive the name "whale" such as the killer and the sperm. That is the reason for the confusion. Historically, "whale" was any cetacean captured by whalers, that is why large odontocetes have also received the name of "whales." Best wishes, Aldemaro Romero, Ph.D.