Other Common Names
Spotter, Gulf Stream spotted dolphin, spotted porpoise, long-snouted dolphin.[11]
[11] See also p. 110. The common name "long-snouted dolphin" was once widely used for this species. It is now more frequently used for Stenella longirostris, also known as the spinner dolphin.
Description
Atlantic spotted dolphins reach a maximum adult length of 7.5, perhaps 8 feet (2.3 to 2.4 m). They are generally more robust in body shape than the other species of Stenella, closely resembling Atlantic bottlenosed dolphins in that regard, though the Atlantic spotted dolphins tend to be more slender.
The dorsal fin is distinctly back-curved and pointed on the tip, also closely resembling that of the Atlantic bottlenosed dolphin.
As the common name suggests, the Atlantic spotted dolphins are marked dorsally with numerous grayish-white spots on a darker background and ventrally with dark spots on a lighter background, though the extent of the spotting and the additional details of coloration change with age.
Immature animals lack spots completely. They are dark gray or purplish gray on the back, becoming lighter gray on the sides and white on the belly. The cape along the back is distinctly separated from the lighter gray coloration of the sides. The flippers and the trailing edge of the flukes are darker than the rest of the body.
As they age, the Atlantic spotted dolphins develop grayish-white spots, first low on the sides, spreading upward. During this stage, the cape becomes less distinct, and dark spotting begins to develop on the belly, the spots increasing in number with increasing age. In adult animals, the belly is often extensively covered with dark blotches but never becomes completely black. The lips may be white, and the beak is characteristically tipped with white, a feature which may aid in identification at sea.
The Atlantic spotted dolphins have a spinal blaze and a light line which extends from the flipper to the eye.