Natural History Notes
Little is known of the natural history of the Atlantic spotted dolphins. The species occurs in herds of up to several hundred individuals, though groups of 50 or fewer (6-10) are more common. They are often seen jumping clear of the water and habitually ride the bow wave of moving vessels. As they do, the distinct cape or band of purplish gray on the back of younger animals and the spotting pattern of older animals may be visible.
Atlantic spotted dolphins feed primarily on squid but may also take carangid fishes, small eels, herring, or anchovies.
May Be confused With
Atlantic spotted dolphins, particularly young animals, may be easily confused with Atlantic bottlenosed dolphins because of the similarities in color pattern and general body shape. However, the Atlantic spotted dolphins have considerable purplish gray in their background colors and the Atlantic bottlenosed dolphins are more dark gray to brownish gray. This along with considerable differences in the overall sizes of the two species should permit positive identification. In general, the key differences between spotted and bottlenosed dolphins are as follows:
| Atlantic Spotted Dolphin | Atlantic Bottlenosed Dolphin |
|---|---|
| MAXIMUM SIZE | |
| To 7.5-8 feet (2.3-2.4 m). | To 8-10 feet (2.4-3.1 m)inshore, to as much as 12 feet(3.7 m) offshore. |
| BODY COLOR | |
| Dark purplish gray on back;lighter gray on sides andbelly; body becomesincreasingly spotted with age. | Dark gray on back; lightergray on sides; white or pinkon belly (old animals mayhave a few spots on belly,but most are not spotted). |
| HEAD AND BEAK | |
| Head more slender; beaklonger; lips and top of snoutoften white. | Head robust; beak short;beak usually uniformly gray(older animals' beak may bewhite at tip). |
| NORMAL DISTRIBUTION | |
| Usually found more than 5miles offshore; most commoninside 100-fathom curve. | Usually more coastal, oftenascending rivers and enteringlagoonal and estuarineareas. |
Young Atlantic spotted dolphins are so similar in appearance to the Atlantic bottlenosed dolphins that the frequent reports of mixed schools of the two species are probably occasioned by groups of spotted dolphins which include some young, still unspotted animals.
Atlantic spotted dolphins might also be confused with bridled dolphins. The two can be most readily distinguished by the following characteristics:
| Atlantic Spotted Dolphin | Bridled Dolphin |
|---|---|
| BODY SHAPE | |
| Usually robust, often likethat of the Atlanticbottlenosed dolphin. | More slender, more likethat of the Atlantic stripeddolphin. |
| BODY COLOR | |
| Spotted; purplish gray onback; lighter gray on sidesand belly becomingincreasingly spotted with age.As animals becomes morespotted, cape become lessdistinct. Body has spinalblaze and light line fromflipper to eye. | Spotted; side of head lightgray; body has stripe fromflipper to corner of mouth,though the stripe tends tofade as spotting increases.Cape on top of head moredistinct that on Atlanticspotted dolphin. Body has nospinal blaze. |