SCIENTIFIC CLASSIFICATION
Taxonomy, begun by Carl Linnaeus in the 18th century, is the orderly classification of plants and animals according to their presumed natural relationships. According to this system, dolphins are classified as follows:


The family Delphinidae is the largest cetacean family and its members are commonly referred to as "ocean dolphins." Delphinidae is divided into 6 subfamilies. The following chart lists both the common name and scientific name for each species and gives a picture, physical description, and location.

NOTE: The following dolphin images and information are from the National Audubon Society Guide to Marine Mammals of the World.

Subfamily: Cephalorhynchinae
Chilean Dolphin
(Cephalorhynchus eutropia)

Physical Characteristics:
- Small size
- Rounded dorsal fin
- Subtle pigmentation dominated by shades of gray on back and sides

Location:
- Inshore and coastal waters of southwestern South America
Commerson's Dolphin
(Cephalorhynchus commersonii)

Physical Characteristics:
- Small body size, with low-profile, rounded dorsal fin
- Conical head with small or inconspicuous beak
- Striking black-and-white, or black, white, and gray color pattern

Location:
- Coastal distribution off southern South America and Kerguelen Islands
Heaviside's Dolphin
(Cephalorhynchus heavisidii)

Physical Characteristics:
- Small body size, with triangular dorsal fin
- Lack of a pronounced beak
- Well-demarcated, black-and-gray dorsal and side color pattern

Location:
- Highly restricted coastal distribution off southwestern Africa
Hector's Dolphin
(Cephalorhynchus hectori)

Physical Characteristics:
- Small body size
- Conical head with no beak
- Rounded dorsal fin with undercut rear margin
- Well-demarcated, black, white, and gray coloration

Location:
- Distribution limited to coastal waters of New Zealand


Subfamily: Stenoninae
Rough-Toothed Dolphin
(Steno bredanensis)

Physical Characteristics:
- Long beak with no crease at melon
- Large flippers and prominent, tall dorsal fin
- Distinctive dorsal cape that narrows between blowhole and dorsal fin
- White lips and throat
- Irregular spotting and blotching on ventral surface

Location:
- Occurs worldwide, mainly in warm deep waters
Tucuxi
(Sotalia fluviatilis)

Physical Characteristics:
- Small body
- Low-profile, triangular dorsal fin
- Well-defined, moderate-length beak
- Evenly light gray dorsal coloration

Location:
- Coastal distribution in tropical and subtropical western Atlantic, plus throughout Amazonia
Atlantic Hump-Backed Dolphin
(Sousa teuszii)

Physical Characteristics:
- Distinctive hump at base of small dorsal fin (much less pronounced in East)
- Long slender beak
- Gray, pink, white, or speckled coloration

Location:
- Occurs in shallow nearshore waters of eastern Atlantic Ocean
Indo-Pacific Hump-Backed Dolphin
(Sousa chinensis)

Physical Characteristics:
- Distinctive hump at base of small dorsal fin (much less pronounced in East)
- Long slender beak
- Gray, pink, white, or speckled coloration

Location:
- Occurs in shallow nearshore waters of western Pacific and Indian Oceans


Subfamily: Delphininae
Risso's Dolphin
(Grampus griseus)

Physical Characteristics:
- Broad head with no beak
- Cleft melon
- Tall, erect dorsal fin
- Extensive linear scarring on adults
- Light, almost white appearance of older individuals

Location:
- Occurs worldwide in tropical and warm temperate waters
Common Bottlenose Dolphin
(Tursiops truncatus)

Physical Characteristics:
- Robust body with short to medium-length beak
- Large falcate dorsal fin
- Basically gray body with muted color pattern

Location:
- Often seen very near shore and in estuaries
- Cosmopolitan distribution
Indo-Pacific Bottlenose Dolphin
(Tursiops aduncus)

Physical Characteristics:
- Robust body with medium length beak
- Large, falcate dorsal fin
- Basically gray body, darker dorsally
- Dark spotting on belly and sides of adults in most regions

Location:
- Found mainly near shore in warm waters of western Pacific and Indian Oceans
Fraser's Dolphin
(Lagenodelphis hosei)

Physical Characteristics:
- Short, barely noticeable beak
- Small, triangular, somewhat falcate dorsal fin
- Small flippers
- Broad dark stripe from face to anus

Location:
- Tropical, deepwater distribution
Atlantic White-Sided Dolphin
(Lagenorhynchus acutus)

Physical Characteristics:
- Short, inconspicuous beak
- Bold white patch on side
- Yellowish-tan streak on flank just above white patch
- Sharply demarcated pigmentation zones
- White of belly extends onto side above flipper

Location:
- Limited to temperate waters of North Atlantic
Pacific White-Sided Dolphin
(Lagenorhynchus obliquidens)

Physical Characteristics:
- Inconspicuous beak
- Large, strongly falcate bicolored dorsal fin
- Light gray "suspenders" along back
- Prominent, light gray patch on foreside
- Black lips and bold black line demarcating white belly

Location:
- Confined to medium latitudes of the North Pacific
Dusky Dolphin
(Lagenorhynchus obscurus)

Physical Characteristics:
- Prominent, falcate, bicolored dorsal fin
- Inconspicuous beak
- Pointed gray blazes on sides below dorsal fin

Location:
- Distributed in cool temperate waters of Southern Hemisphere
Hourglass Dolphin
(Lagenorhynchus cruciger)

Physical Characteristics:
- Short stubby beak
- Large, centrally placed dorsal fin, sometimes strongly hooked
- Striking black-and-white coloration, sharply demarcated

Location:
- High-latitude, offshore distribution in Southern Hemisphere
Peale's Dolphin
(Lagenorhynchus australis)

Physical Characteristics:
- Prominent, falcate dorsal fin
- Dark face
- Light areas on flank and foreside, separated by wide diagonal dark stripe
- White patch at base of flipper

Location:
- Coastal and inshore distribution off southern South America
White-Beaked Dolphin
(Lagenorhynchus albirostris)

Physical Characteristics:
- Short thick beak, usually white
- Prominent, falcate dorsal fin
- Diffuse coloration with broad, grayish-white blazes on sides
- Grayish-white saddle on back behind dorsal fin

Location:
- Limited to cool waters of North Atlantic
Long-Beaked Common Dolphin
(Delphinus capensis)

Physical Characteristics:
- Muted crisscross pattern on sides
- Tan or yellowish-tan patch on sides forward of dorsal fin
- Pale gray flanks and caudal peduncle
- Flipper stripe relatively wide, well demarcated from white throat but not from gray side
- Tall dark dorsal fin

Location:
- Found in warm coastal waters of Atlantic, Pacific, and Indian Oceans
Short-Beaked Common Dolphin
(Delphinus delphis)

Physical Characteristics:
- V-shaped dark saddle, with downward-oriented point on side directly below dorsal fin
- Light gray or yellowish patch on sides forward of dorsal fin
- Light gray flanks and caudal peduncle
- Tall dark dorsal fin, often with gray or whitish area in center

Location:
- Widespread in tropical and temperate waters of Atlantic and Pacific Oceans
Atlantic Spotted Dolphin
(Stenella frontalis)

Physical Characteristics:
- Three-part coloration: dark gray back, lighter sides, white belly
- Spotting ranges from absent in calves to striking in some adults
- Combination of shoulder blaze and spotting is diagnostic
- White-tipped beak

Location:
- Occurs only in tropical and warm temperate Atlantic
Pantropical Spotted Dolphin
(Stenella attenuata)

Physical Characteristics:
- White-tipped beak
- Prominent dark dorsal cape that dips low onto sides
- Light gray swath sweeping upward on caudal peduncle
- Variable degree of spotting

Location:
- Tropical to warm temperate distribution
Clymene Dolphin
(Stenella clymene)

Physical Characteristics:
- Dark cape with rounded dip below dorsal fin
- "Mustache" mark on upper surface of beak
- Eye-to-flipper stripe that widens toward flipper

Location:
- Endemic to tropical and subtropical Atlantic
Spinner Dolphin
(Stenella longirostris)

Physical Characteristics:
- Usually slender build
- Long, narrow beak and flat melon
- Dorsal fin erect, sometimes canted forward
- Ventral margin of dorsal cape almost parallel to body axis

Location:
- Tropical distribution
Striped Dolphin
(Stenella coeruleoalba)

Physical Characteristics:
- White to light gray shoulder blaze, sweeping back and up toward dorsal fin
- Bold, narrow black stripes from eye to anus and eye to flipper

Location:
- Distribution mainly seaward of continental shelf in tropical and warm temperate seas


Subfamily: Lissodelphinae
Northern Right Whale Dolphin
(Lissodelphis borealis)

Physical Characteristics:
- Slender bodies with no dorsal fin
- Stark black-and-white color patterns (more white on Southern species)

Location:
- Cold temperate waters of North Pacific
Southern Right Whale Dolphin
(Lissodelphis peronii)

Physical Characteristics:
- Slender bodies with no dorsal fin
- Stark black-and-white color patterns (more white on Southern species)

Location:
- Cold temperate waters of Southern Hemisphere


Subfamily: Globicephalinae
Long-Finned Pilot Whale
(Globicephala melas)

Physical Characteristics:
- Bulbous melon with no noticeable beak
- Broad-based, low-profile, falcate dorsal fin positioned far forward on body
- Black or dark brown body color
- White or light gray saddle on back behind dorsal fin
- White or light gray blaze above and behind eye, especially in Southern Hemisphere

Location:
- Cool temperate to subpolar distribution in North Atlantic and Southern Hemisphere
Short-Finned Pilot Whale
(Globicephala macrorhynchus)

Physical Characteristics:
- Bulbous or squarish melon with no discernible beak in adults
- Broad-based, low-profile, falcate dorsal fin positioned far forward on body
- Black or dark brown body color
- Large, often conspicuous light gray saddle behind dorsal fin

Location:
- Pantropical and warm temperate distribution
Killer Whale (Orca)
(Orcinus orca)

Physical Characteristics:
- Tall, erect dorsal fin, more prominent in adult male
- Large rounded flippers
- Distinctive black-and-white color pattern
- Large size relative to other dolphins

Location:
- Cosmopolitan distribution
False Killer Whale
(Pseudorca crassidens)

Physical Characteristics:
- Tall, erect, falcate dorsal fin
- Small, rounded or conical head with no beak
- Dark coloration
- Hump on leading edge of flippers

Location:
- Primarily tropical to warm temperate distribution
Pygmy Killer Whale
(Feresa attenuata)

Physical Characteristics:
- Small, mostly dark body
- Rounded head with white lips
- Large, erect, falcate dorsal fin
- Muted dark dorsal cape and slightly lighter sides

Location:
- Mainly offshore, pantropical distribution
Melon-Headed Whale
(Peponocephala electra)

Physical Characteristics:
- Small body size, with little or no beak
- Prominent, erect dorsal fin
- Tapered, pointed flippers
- Dark body color

Location:
- Mainly pelagic, tropical distribution


Subfamily: Orcaellinae
Irrawaddy Dolphin
(Orcaella brevirostris)

Physical Characteristics:
- Head rounded in profile
- Small triangular dorsal fin
- Even gray coloration

Location:
- Endemic to southeastern Asia, Indonesia, northern Australia


BASIC ANATOMY
This diagram shows the basic anatomy of a dolphin and is followed by definitions of each part.


Blowhole - nostril, or respiratory opening, of a cetacean; odontocetes have one, mysticetes two.

Melon - the often bulging forehead of a tooth cetacean

Rostrum - specifically the upper jaw of a cetacean; also sometimes used to refer to a beak that encompasses both the upper and lower jaws.

Beak - the forward-projecting jaws of certain toothed cetaceans.

Flippers - variably shaped, often paddle-like limbs of a cetacean, pinniped or sirenian.

Axillae (singular: axilla) - the "armpit" regions at the posterior base of the flippers of a cetacean.

Median Notch - cleavage between the paired flukes of a cetacean.

Flukes - the two horizontally flattened, fin-like structures that comprise a cetacean's tail.

Caudal Peduncle - that portion of a cetacean's or sirenian's body behind the dorsal fin (only cetaceans) and anterior to the flukes. Also called the tail stock.

Dorsal Fin - the fin along the midline of the back of a cetacean. Most cetaceans have a dorsal fin.



REFERENCES
Knopf, Alfred, A., ed. National Audubon Society Pocket Guide: Familiar Marine Mammals of North America. New York: Chanticleer Press, 1995.

Knopf, Alfred, A., ed. National Audubon Society Guide to Marine Mammals of the World. New York: Chanticleer Press, 2002.

Samansky, Terry S. Starting Your Career as a Marine Mammal Trainer. 2nd ed. Napa, CA: DolphinTrainer.com, 2002.