Identification Guide | Marine Mammal

Marine mammals can be difficult to identify at sea. Even under ideal conditions, an observer often gets little more than a brief view of a splash, blow, dorsal fin, head, flipper, or back, and this is often at a great distance. Rough weather, glare, fog, or other bad sighting conditions compound the problem. Even experts often must log a sighting as “unidentified” or on an easily confused pair or group of species. In all cases, this designation, accompanied by a detailed description is preferable to recording an incorrect identification.

Marine Mammals of India – A field guide
Contact Dipani Sutaria or Pooja Gupta to get a copy of this guide

Character Matrix 1: Beaked Dolphins WITH prominent markings. All these species are about 2m long.

Species	Distinctive marks and colouration	Teeth (pairs in each jaw)
Long-beaked common dolphin , Delphinus delphis	Dark brown to black above, including appendages White below Yellow front flank patches Rear flanks and tail stock light grey	Small, pointed (47– 67)
Indian Ocean common dolphin Delphinus delphis tropicalis	slightly longer than the common dolphin	54-67 teeth in upper jaw side 52-64 teeth in lower jaw side
Spinner dolphin , Stenella longirostris	Some grey throughout, others grey with a white belly Yet others with a three-part colour pattern — grey cape, light grey sides, white belly	Sharply pointed (45– 65) Please check the groove between the two lower jaws; do the jower jaws merge at the tip or do they not?
Striped dolphin, Stenella coeruloealba	Dark stripe from behind eye to anus Belly white Sides grey Dark stripe from eye to flipper	Small and sharp (45 –50)
Pan-tropical spotted dolphin, Stenella attenuata	Stenella attenuata Dark grey cape from top of head to halfway down the animal Lighter grey below; white spots, becoming bigger & more numerous with age	Small (40)

Character Matrix 2: Beaked Dolphins WITHOUT prominent markings.

Species	Length (m)	Prominent Features	Colour
Rough-toothed dolphin , Steno bredanensis	Max.2.4	Large eyes Head conical, sloping evenly towards the tip of the snout No prominent melon	Body dark grey with a narrow dorsal cape Belly, lips & lower jaw white
Indo-Pacific humpback dolphin , Sousa chinensis	Newborn 1.0 Max. Male 3.2 Female 2.5	Dorsal fin sits on distinct hump or ridge midway along the back Hump under the fin is not prominent Melon is not as prominent as in S. plumbea	Adult animals of the region very pale, almost white, or overall light gray and mottled Young lighter grey 32-38 teeth in upperjaw side; 29-38 in lower jaw side
Indian Ocean humpback dolphin , Sousa plumbea	Max female: 2.6m Max male: 2.8m	Hump under the fin is very prominent Melon is very prominent	Adults are usually brownish gray with very little mottling of white or pink 33-39 teeth in upper jaw side; 31-37 in lower jaw side
Bottlenose dolphin , Tursiops truncatus	Newborn 1.0 Max. Male 4.0 Female 3.6	Well-formed melon separated from stocky snout by a marked crease Dorsal fin is tall and falcate	teeth count is 18-27 in any one side of jaw Belly off-white Sides of the head & body light grey, gradually becoming deeper until it forms a dark bluish-grey cape on the back
Indo-Pacific bottlenose dolphin , Tursiops aduncus	newborn is 85cm-112cm Adult 2.7m	melon less convex than in common botlenose dolphin dorsal fin is larger and less falcate than common bottlenose dolphin	teeth count 21-29 in one side of each jaw belly has spots dark ring around the eye lighter in colour than common bottlenose dolphins
Fraser’s dolphin , Lagenodelphis hosei	Newborn 1.0 Max. 2.6	Beak short but well-defined Flippers and dorsal fin short & pointed	Dark brownish-grey on the sides Pink or white on the belly Bold dark grey striping on the flippers & on the face and along the sides, giving the face a masked effect

Character Matrix 3: Irrawaddy Dolphin, Risso’s Dolphin & Finless Porpoise

Species	Length (m)	Colour	Dorsal fin	Flippers	Teeth (pairs)	Neck crease
Irrawaddy dolphin , Orcaella brevirostris	Newborn 1.0 Max.Male 2.7 Female 2.3	Pale grey Darker above, paler below	Small, lying at midback	Large, with curved leading edge	Peglike Upper jaw: 17-20 Lower jaw: 15-18	Present
Risso’s dolphin , Grampus griseus	Newborn 1.2 Max. Male 3.8 Female 3.3	Grey body covered extensively with white scarring & blotching Some animals, especially older ones, appear almost white An anchor-shaped white chest patch	Tall, slender & falcate Generally a darker shade of grey than the rest of the body Located at midback	Long & falcate, with pointed tips	Peglike Upper jaw: No teeth Lower jaw: Upto 7 Teeth often badly worn in older individuals & some missing entirely	Absent
Finless porpoise , Neophocaena phocaenoides	Newborn 0.55 Max. 1.9 Males slightly larger	Uniform grey, with often a bluish tinge Ventral surface lighter Whitish zones on throat & sometimes on upper lip	Absent Skin on the midback dark & covered with tubercles	Long, tapering to a blunt tip	Spade shaped 13-22 in each jaw	Slight depression behind the blowhole

Character Matrix 4: The Blackfish

Species	Length (m)	Colour	Dorsal fin	Flippers	Teeth (pairs)
Pygmy killer whale , Feresa attenuata	Newborn 0.8 Max. 2.5	Grey to blue-black Darker cape from top of head to dorsal fin Lips & tip of lower jaw white	Curved along leading edge, rounded at tip	High pointed	Upper jaw: 8-11 & Lower jaw: 11-13
False killer whale Pseudorca crassidens	Newborn 1.6 Max. Male 5.9 Female 5.1	Black Lighter areas on head & chest	Broad hump on leading edge	Upright, slightly rounded at tip, located at mid-back	Conical 7 to 12 in each jaw
Melon-Headed whale , Peponocephala electra	Newborn 1.0 Max. 2.7	Black on back and sides, slightly lighter on belly Lips, anal and genital areas may appear light-grey, white or pink	Long,generally pointed	Tall, distinctly back-curved	Small, sharply pointed Upper jaw: 20-25 & Lower jaw:22-24
Short-finned pilot whale Globicephala macrorhynchos	Newborn 1.4 Max.Male 7.2 Female 5.1	Grey-black overall Many animals have a lighter chest patch & a grey streak behind the eyes	Falcate, up to one-sixth of body length	Low rounded	< 7-9 in each jaw

Character Matrix 5: The Small Sperm Whales

Species	Length (m)	Head	Dorsal fin	Group Size	Teeth (pairs)
Pygmy sperm whale , Kogia breviceps	Newborn 1.2 Max. 3.4	Rectangular in adults	Small, located behind mid-point of back	Small groups of fewer than five individuals	Curved, needle-like Lower jaw: 10-16
Dwarf sperm whale Kogia sima	Newborn 1.0 Max. 2.7	Short, blunt and squarish snout Some irregular grooves/creases on the throat	Tall, broad-based, with a concave trailing edge, located farther forward than in the Pygmy Sperm Whale	Up to 10 individuals	Upper jaw: 7-12 & Lower jaw: 1-3 may occur

Character Matrix 6:The Beaked Whales ( note position & shape of blowhole, flipper shape, head shape, fin position and teeth)

Species	Length (m)	Colour	Teeth	Position of Teeth in Lower Jaw(from tip)
Ginkgo-toothed beaked whale Mesoplodon ginkgodens	Max. about 5 (probably)	Living specimens not examined General colour of dead ones “midnight black” Many oval white scars on sides & belly	Ginkgo tree leaf shaped 10 cm or more wide at base	One-fourth
Blainville’s beaked whale Mesoplodon densirostris	Newborn 2.0 Max. 5.2	Male dark all over Female pale (usually white) below Prominent oval scarring & scratches overall	Two forward projecting massive teeth on prominent raised arches on each side of lower jaw in male Jaw bone greatly enlarged below tooth	One-third
Cuvier’s beaked whale Ziphius cavirostris	Newborn 2.8 Max. 7.5	Variable General body colour maybe “acorn brown, tan,light brown or metal blue” Males grow lighter with age, the head & nape eventually change from grey-brown to white	Two conical teeth only in the male	At tip
Longman’s beaked whale Indopacetus pacificus	New born: 2.9m Max. 9m	Umber brown to brownish gray with a light coloured head Steep buldging forehead larger dorsal fin like a dolphin fin and behind midpoint of body Body covered with circular scars	Oval teeth One pair, hidden in the gums	At tip
Deraniyagala’s beaked whale Mesoplodon hotaula	Max. 4.8	Counter shaded – dark grey with lighter beak small dorsal fin placed two thirds from beak Un-notched fluke No linear scars like in other beaked whales	Males have one pair of S shaped recurved tusks Females do not have tusks	Middle

Character Matrix 7:The Rorquals

Species	Length (m)	Baleen	Throat grooves	Flipper to total length ratio	Distance of fin from tail relative to total length	Ridges on top of head	Flippers	Colour
Minke whale Balaenoptera acutorostrata	Newborn 2.7 Max. 10.7	Yellowish white, including frayed edge	About 50	1:8	One-third	1	Blue-grey with white patch above, white below	Dark slate grey, paler grey or white on belly
Bryde’s whale Balaenoptera edeni	Newborn 3.6 Max. 14.0	Front plates whitish, back plates blackish, long stiff bristles	40-50	1:10-1:12	Greater than one-third	3	Dark bluish grey above, grey below	Dark grey Some white on throat & chin
Blue whale Balaenoptera musculus	Newborn 6.4 Max. 28.0	Jet black including frayed edge	55-100	1:7	One-fourth	1	Slate-blue above	Bluish-grey May be mottled & blotched
Humpback whale Megaptera novaengliae	Newborn 4.3m Max. 11-17m	Dark gray baleen plates with coarse gray bristles hanging	14-35	1:3	Greater than one-third	1	Black above, white below	Dorsal surface is black with knobbly outgrowths White below Fluke has a prominent notch with a serrated trailing edge Fins very long with tubercles