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  • Tursiops aduncus

    Common Name: Indo-pacific bottlenose dolphin

    Tursiops spp: The Tursiops genus has been split into two, T. truncatus and T. aduncus. The taxonomy of this genus is still not thoroughly clear, however due to considerable geographic variations, additional species may be recognised in the future.

    General Description: Indo-Pacific bottlenose dolphins have a large, robust head and trunk, a gently curving melon with a sharp crease before the beak. The beak is moderately long and slender compared to the common bottlenose dolphin. The dorsal fin is tall and triangular (not as falcate as common bottlenose dolphins) and larger than in common bottlenose dolphins. The flippers are long and pointy at tips.
    The colouration is variable, but usually shades of light grey on the flanks, grading to white or pink on the belly. Belly is marked with speckles or black spots in adults. Usually a dark ring is present around the eye.

    Size: Calves: Length of animals at birth is approximately 85cm – 112cm. Adults: Adult dolphins are between 2.7 m, males tend to be slightly larger than the females. Maximum weight is around 230kg.

    Appearance At Sea: While Tursiops is easy to identify at sea given the relatively short beak, robust body, convex melon, sharp beak crease and body colour pattern, it is not easy to separate between T. trunctus and T. aduncus. A suite of characteristics need to be checked, and good pictures is the best way to confirm.

    Found In: Occur on the continental shelf in shallow coastal and around oceanic island groups.

    Records from India:

    Date : 1846
    Details : Skull from Bay of Bengal, the type of Delphinus eurynome, in the British Museum (Natural History).
    Sources : De Silva, P.H.D.H. (1987) Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf of Aden and from the Red Sea.Journal of the Bombay Natural History Society, 84(3), 505-525.va, 1987.


    Date : 1848
    Details : Delphinus perniger described by Elliot from the Bay of Bengal; stuffed skin in the Museum of the Asiatic Society, Calcutta.
    Sources : DJerdon, T.C.(1867) A Handbook of the Mammals of India. Indian edition, 1989, Mittal Publications, New Delhi.335 pages.;De Silva, P.H.D.H. (1987) Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf Gulf of Aden and from the Red Sea.Journal of the Bombay Natural History Society, 84(3), 505-525.va, 1987.


    Date : 1866
    Details : Delphinus godama described by Owen from collections made by Sir Walter Elliot near Visakhapatnam; the skull gifted by Elliot to the British Museum (Natural History).
    Sources : Jerdon, T.C.(1867) A Handbook of the Mammals of India. Indian edition, 1989, Mittal Publications, New Delhi.335 pages.;De Silva, P.H.D.H. (1987) Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf Gulf of Aden and from the Red Sea.Journal of the Bombay Natural History Society, 84(3), 505-525.va, 1987.


    Date : 1904
    Details : A single specimen of Tursiops gilli obtained from Travancore.
    Sources : Pillay, R.S.N. (1926) List of cetaceans taken in Travancore from 1902 to 1925.Journal of the Bombay Natural History Society, 31(3), 815-817., 1926.


    Date : 01-10-1904
    Details : Specimen caught off Trivandrum may be this species.
    Sources : Lydekker, R. (1905) On dolphins from Travancore.Journal of the Bombay Natural History Society, 16(4), 730-736.


    Date : 01-02-1908
    Details : Two specimens of Tursiops dawsoni purchased measuring 2.7 and 2.8 m (9 feet and 9 feet 4 inches) by the Trivandrum museum; one skeleton in the British Museum (Natural History).
    Sources : Pillay, R.S.N. (1926) List of cetaceans taken in Travancore from 1902 to 1925.Journal of the Bombay Natural History Society, 31(3), 815-817.;De Silva, P.H.D.H. (1987) Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India.


    Date : 21-12-1978
    Details : One male caught off Calicut.
    Sources : James, P.S.B.R. & Lal Mohan, R.S. (1987) The Marine Mammals of India.Marine Fisheries Information Service Technical & Extension Series, 71, 1-13. & Lal Mohan, 1987.

    Could Be Confused With: In areas where they overlap in distribution, common bottlenose dolphins can be confused with Indo-Pacific bottlenose dolphins (Tursiops aduncus), rough toothed dolphins (Steno bredanensis), and spotted dolphins (Stenella spp.). They can be distinguished based on the following characteristics:

    Species : Common Bottlenose Dolphin
    Size : Average size 3m, often more
    Build : Bulky
    Beak : Short beak, clearly marked off from melon
    Markings : No spots


    Species : Indo-Pacific bottlenose dolphin
    Size : Average size, 2.7 m
    Build : Robust, slender compared to Tursiops truncatus
    Beak : Moderately long beak, less convex melon than T.truncatus
    Markings : Flecks or black spots on the belly


    Species : Spotted Dolphin
    Size : Around 2.4 m
    Build : Slender
    Beak : Longish beak, well demarcated from melon
    Markings : Many regular spots
    Species : Rough-toothed dolphin


    Size : Seldom more than 2.4m
    Build : Slender
    Beak : Long, thin beak not clearly demarcated from melon
    Markings : Irregular blotches on belly

    Diagnostic Features at sea:Can be distinguished from common bottlenose dolphins based on overall size, shape of body, shape of head and beak, spots on the belly, shape of dorsal fin and colouration.

    Stranded specimens: Stranded individuals can best be identified based on total length, shape of fin, length of beak and teeth count between 21-29 pairs in each jaw.

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    Bottlenose Dolphin

    Bottlenose Dolphin breaching in the bow wave of a boat

    Size comparison against an average human

    Conservation Status

    Least Concern (IUCN 3.1)

    Scientific Classification

    Kingdom Animalia
    Phylum Chordata
    Class Mammalia
    Subclass Eutheria
    Order Cetacea
    Suborder Odontoceti
    Family Delphinidae
    Genus Tursiops
    Species T. truncatus

    Binomial Name

    Tursiops truncatus

    ( Montagu, 1828 )

    Bottlenose Dolphin range.

    Source: Wikipedia