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  • Identification Guide

    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
    • No prominent melon
    • Body dark grey with a narrow dorsal
    • 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
    leading edge
    • Peglike
    • Upper jaw: 17-20
      Lower jaw: 15-18
    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 &
    • Generally a
      darker shade of
      grey than the
      rest of the body
    • Located at
    Long & falcate,
    with pointed
    • Peglike
    • Upper jaw: No teeth
      Lower jaw: Upto 7
    • Teeth often badly
      worn in older
      individuals & some
      missing entirely
    Finless porpoise , Neophocaena phocaenoides
    • Newborn 0.55
    • Max. 1.9
    • Males slightly
    • Uniform grey, with
      often a bluish tinge
    • Ventral surface
    • Whitish zones on
      throat & sometimes
      on upper lip
    • Absent
    • Skin on the
      midback dark &
      covered with
    Long, tapering to
    a blunt tip
    • Spade shaped
    • 13-22 in each jaw
    behind the

    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
    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
    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
    • 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
      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
    • Living specimens not
    • 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
    Blainville’s beaked whale Mesoplodon densirostris
    • Newborn 2.0
    • Max. 5.2
    • Male dark all over
    • Female pale (usually white)
    • Prominent oval scarring &
      scratches overall
    • Two forward projecting massive
      teeth on prominent raised arches
      on each side of lower jaw in
    • Jaw bone greatly enlarged below
    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

    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