ATLANTIC BOTTLENOSED DOLPHIN (T) 



Tursiops truncates (Montague 1821) 



Other Common Names 



Bottlenosed porpoise, gray porpoise, common porpoise.'^ 



Description 



Atlantic bottlenosed dolphins reach a maximum overall 

 length of about 12 feet (3.7 m) and weigh in excess of 1,430 

 pounds (650 kg). They have relatively stubby snouts and 

 dorsal fins, which are broad at the base, tall, and falcate. 

 Coloration varies slightly, but individuals are usually dark 

 gray on the back, lighter gray on the side, grading to white or 

 pink on the belly. Old females may have spots on the belly. 

 The dark coloration of the back often appears as a highly 

 distinct cape, particularly on the head. 



Natural History Notes 



Atlantic bottlenosed dolphins often occur in groups of up 

 to several hundred individuals which usually consist of 

 aggregations of small groups of no more than a dozen animals 

 each. They frequently associate with the Atlantic pilot 

 whales and are frequently found accompanying the right and 

 hump back whales travelling along the Atlantic coast of 

 Florida. 



Atlantic bottlenosed dolphins have catholic tastes, 

 feeding on shrimp, eels, catfish, menhadden mullet, and 

 miscellaneous trash fish, to mention only a few. They are 

 frequently found near shrimp boats, feeding on fish stirred up 

 by the trawls or on discarded trash fish. 



They sometimes move in to ride the bow wave of a vessel, 

 turning on their sides, sometimes spinning completely 

 around on their longitudinal axis when doing so. Individuals 

 may also turn their heads downward or to the side. They are 

 often found close to shore, in bays and lagoons, and 

 sometimes venture up the larger rivers. Some individuals, 

 especially the larger animals, are found as far offshore as the 

 edge of the continental shelf. Atlantic bottlenosed dolphins 

 sometimes ride the surf. Individuals may jump clear of the 

 water as high as 15-20 feet (4.6-6.1 m), a behavior on which 

 aquarium shows have capitalized. 



Members of this species are the dolphins most commonly 

 maintained in captivity at zoos, aquariums, marine parks, 

 and research institutions. For that reason, they are perhaps 

 more familiar to the general public than any other species of 

 porpoise, dolphin, or whale. 



May Be Confused With 



From at least Cape Hatteras southward, the range of the 

 Atlantic bottlenosed dolphins distributed in inshore areas 

 may overlap with that of Atlantic spotted dolphins, 

 particularly during the spring and summer, when the 

 Atlantic spotted dolphins move inshore. There the two 



species may be confused. The Atlantic bottlenosed dolphins 

 and the Atlantic spotted dolphins can be distinguished, 

 however, by the following characteristics: 



Atlantic Atlantic 



Bottlenosed Dolphin Spotted Dolphin 



MAXIMUM SIZE 



8 feet to as much as 12 feet 



(2.4 to 3.7 m). 



7.5-8 feet (2.3-2.4 m) 



COLORATION 



Not spotted (old females may 

 have spots on belly); dark 

 gray on back; light gray on 

 sides; white or pink on belly. 



Dark purplish gray on back; 

 lighter gray on sides and 

 belly; body becomes increas- 

 ingly spotted with age. 



HEAD AND BEAK 



Head robust; beak relatively Head more slender; beak 

 short. longer. 



Some Atlantic bottlenosed dolphins are distributed well 

 offshore as far as the edge of the continental shelf. Those 

 individuals may be confused with either rough-toothed 

 dolphins (p. 135) or with grampus (p. 96). They may be 

 distinguished from rough-toothed dolphins by the following: 



Atlantic Bottlenosed 

 Dolphin 



Rough- Toothed Dolphin 



BODY COLOR 



Dark gray on back; light 

 gray on side; white or pink on 

 belly. 



Dark gray, almost purplish 

 with yellow spots; lighter on 

 belly. 



SNOUT 



Relatively short and stubby, 

 and clearly demarcated from 

 forehead; usually all gray; 

 some older individuals have 

 white-tipped snouts and/or 

 white lips. 



Long and slender; not clearly 

 demarcated from forehead; 

 lower jaw and lips speckled 

 white. 



See also p. 150 for use of this common name for another species, the 

 harbor porpoise. 



Distinguishing differences between the Atlantic bottle- 

 nosed dolphins in offshore areas and grampus are tabularized 

 on p. 96. 



In northeastern South America the range of the Atlantic 

 bottlenosed dolphin apparently overlaps with that of the 

 Guiana dolphin, which, except for size, it closely resembles 

 (see p. 132). 



Distribution 



The Atlantic bottlenosed dolphins are widely distributed 

 in the temperate and tropical waters of the western North 



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