Cetacea is a scientific order of large aquatic mammals that have forelimbs modified into flippers, a horizontally flattened tail, one or two nostrils at the top of the head for breathing, and no hind limbs. Cetaceans include all whales, dolphins and porpoises.

Odontoceti is a scientific suborder of whales characterized by having teeth and a single blowhole. The word "Odontoceti" comes from the Greek word for tooth, odontos.

Scientists group most dolphins in the scientific family Delphinidae, part of the suborder Odontoceti. Delphinids (at least 36 species of ocean dolphins) include such well known dolphins as bottlenose dolphins and common dolphins as well as pilot whales and killer whales.

Tursiops, which translates as "dolphinlike," is derived from the Latin word Tursio for "dolphin" and the Greek suffix –ops for "appearance".

Scientists believe that early whales arose 50 million years ago from (now extinct) primitive mammals that ventured back into the sea. Two small rod-shaped pelvic bones, buried deep in the body muscle of toothed whales, may be remnants of the hind limbs of these primitive mammals.

Modern forms of both odontocetes and mysticetes appear in the fossil record five to seven million years ago.

The genus Tursiops first appears in the fossil record about five million years ago.