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  • Orcaella brevirostris

    Common Name: Irrawaddy Dolphin

    General Description:  Irrawaddy dolphins resemble Beluga with its stout body, rounded head, well developed bulging eyes and distinct melon but a very short beak.

    It is also similar in appearance to the finless porpoise but is larger and has a dorsal fin. The dorsal fin is small and sickle-shaped with a rounded tip, and is placed well behind the midpoint of the body. Beyond this, a keel extends backwards on to the tail.

    It has broad, long, paddle-like flippers. The mouthline is horizontal. There is a neck crease and the head can be freely moved. The colour of the animal is brown grey – darker above, paling gradually to the belly. Calves are almost dark in colour when born and get lighter as they grow.

    Size: Adult: Male Irrawaddy dolphins grow to a length of 2.7 m, and females to 2.3 m. Weigh 90 to 150 kg. Calves at birth, 90 cm long.

    Appearance At Sea: Irrawaddy dolphins are usually seen alone or in small groups of 3 or 4 upto 7-9, feeding or swimming together.

    This species is quiet and inconspicuous, rising slowly to the surface so that only the rounded head protrudes, and then sinking quickly after blowing. This procedure is repeated 2-5 times at 10-second intervals, and is followed by a deeper dive which takes the dolphin out of view for up to 3 minutes.

    Found In: Irrawaddy dolphins are found in shallow coastal waters, rivers, estuaries, brackish lagoons and mangrove creeks.They feeds on fish and crustaceans.

    Records from India: In India, Irrawaddy dolphins are found in Chilika lagoon and coastal Orissa, coastal West Bengal and the Sundarbans of West Bengal.

    World Distribution: Irrawaddy Dolphins are found in the tropical waters of the Indo-Pacific, from Orissa in India till Philippines in south east Asia. The the specimen was reported from Vishakhatpatnam, Andhra Pradesh.

    Could Be Confused With: There is a possibility of confusion with the finless porpoise in areas where both species occur.

    Diagnostic Features: At sea, globose head and small snub fin.

    Stranded specimens: The body shape is usually sufficient to identify the species. There are 12 to 20 pairs of teeth in the upper jaw and 12 to 18 teeth in each side of the lower jaw. The teeth are peg-like.

    Irrawaddy Dolphin

    Size comparison against an average human

    Conservation Status

    Vulnerable (IUCN 3.1)

    Scientific Classification

    Kingdom Animalia
    Phylum Chordata
    Class Mammalia
    Subclass Eutheria
    Order Cetacea
    Suborder Odontoceti
    Family Delphinidae
    Genus Orcaella
    Species O. brevirostris

    Binomial Name

    Orcaella brevirostris

    ( Gray, 1866 )

    Finless Porpoise range.

    Source: Wikipedia