Orcaella brevirostris   (Owen in Gray,  1866) (Dolphin)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Chordata
Class: Mammalia
Order:Cetartiodactyla
Family:Delphinidae

Description
Size: Male: 2.7 m; Female: 2.3 m.

Weight: 90-150 kg

Color: The color of the animal is grey–darker above, paling gradually to the belly.

The Irrawady Dolphin resembles the Beluga or White Whale Delphinapteras leucas of Arctic waters, with its stout body, rounded head, and distinct melon but no beak. It is also similar in appearance to the Finless Porpoise Neophocaena phocaenoides, but is larger and has a dorsal fin. It has broad, long, paddle-like flippers. Its dorsal fin is small and sickle-shaped with a rounded tip. The mouthline is horizontal. There is a neck crease and the head can be freely moved. There are 12-20 pairs of teeth in the upper jaw and 12-18 teeth in each side of the lower jaw. The teeth are peg-like.

These move in small groups of 6 or less individuals, but at times 15 dolphins may stay together. Not very active, though they do leap on occasions. Breeding season is not well known. Interestingly these dolphins spit water whilst feeding, probably as a means of herding fish.

Similar species: Irrawaddy dolphin may be confused with Finless porpoise or Dugong, in regions where their range overlaps. But unlike the other two species, the Irrawaddy dolphin has a dorsal fin.


Synonym (s)
Orca (Orcaella) brevirostris Owen in Gray, 1866
(Basionym)
Orcaella brevirostris brevirostris Ellerman & Morrison-Scott, 1951
Orcaella brevirostris fluminalis Ellerman & Morrison-Scott, 1951
Orcaella fluminalis Gray, 1871
Orcella brevirostris Anderson, 1871
Orcella fluminalis Anderson, 1871
Phocaena (Orca) brevirostris Owen, 1866

Common Name (s)
• Snubfin Dolphin (English)
• Irrawadi Dolphin (English)
• Irrawaddy Dolphin (English)
• Large India Porpoise
• Porpoise
• Irrawaddy
• Dolphin
• Snubfin
• Dolphin of the Irawadi (English)
• Irrawady Dolphin (English)
Economic Importance and Threats
Threats:  Anthropogenic
(Incidental bycatch, hunting)

Ecology
Habitat:  Estuarine, Coastal
Prey:  Fish and crustaceans.
IUCN Status:  Vulnerable

Biogeography


• Bay of Bengal (Lat: 15) (Long: 90) INDIA
• Andhra Pradesh, Waltair Coast INDIA
• Andhra Pradesh, Vishakhapatnam INDIA (Record: 1866)
• Andhra Pradesh, Vishakhapatnam Harbour INDIA
• Tamil Nadu, Chennai Beach INDIA (Record: 19/11/1977)
• Orissa, Chilika Lake INDIA (Record: 1985-1987, 1915)
• Orissa, Gahirmatha Beach INDIA (Record: 01/1987-03/1987)
• Andhra Pradesh, Waltair INDIA
• Orissa, Satpara INDIA
• Tamil Nadu, Gulf of Mannar INDIA
• Orissa, Bhitarkanika INDIA
• INDIA (Record: 1800-2000)

Literature Source(s)
  • Alfred, JRB; Das, AK and Sanyal, AK (Eds.) (1998) Faunal diversity in India ZSI, Calcutta 1-497 Available at - NCL, Pune
  • UNEP World Conservation Monitoring Centre Available at - http://www.unep-wcmc.org/
  • Saha, SS (1995) Mammalia Wetland ecosystem series 1: Fauna of Chilka lake ZSI, Calcutta 601-610 Available at - NIO Goa
  • (1994) The red data book on Indian animals Vertebrata part 1 ZSI, Kolkata 1-534 Available at - NCL, Pune
  • Zoological Survey of India (Eds) (1991) Animal resources of India (Protozoa to Mammalia) ZSI 1-694 Available at - NCL, Pune
  • Molur, S and Walker, S (1998) Mammals of India. Report summary 1998 Zoos' Print Journal Zoo Outreach Organisation, Coimbatore 13(9) 7 Available at - NCL, Pune
  • Kumaran, PL (2002) Marine mammal research in India: A review and critique of the methods Current Science Indian Academy of Sciences, Bangalore 83(10) 1210-1220 Available at - www.ias.ac.in/currsci/nov252002/1210.pdf
  • Beasley, I; Robertson, KM and Arnold, P (2005) Description of a new dolphin, the Australian snubfin dolphin Orcaella heinsohni sp. n. (Cetacea, Delphinidae) Marine Mammal Science 21(3) Available at - Zoological Records
  • Borkar, M (2005) Marine mammals, turtles and crocodiles: A field manual NIO, Goa 63 pp Available at - NIO
  • Sathasivam K (2004) Marine mammals of India Universities Press(India) private limited, Hyderabad, India 180 pp Available at - NIO, Goa
  • (2003) IUCN Red list of threatened species Available at - http://www.iucnredlist.org/
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org
  • Marine Biological Station, Chennai, Tamil Nadu (2003) Checklist of marine fauna of Tamil Nadu Department of Environment, Government of Tamil Nadu Available at - http://tnenvis.nic.in
  • Dr. Ramesh, R; Dr. Nammalwar, P and Dr. Gowri, VS (2008) Database on coastal information of Tamil Nadu Report Submitted to Environmental Information System (ENVIS) Centre, Department of Environment, Government of Tamil Nadu Institute for Ocean Management, Anna University, Chennai, Tamil Nadu. Available at - http://tnenvis.nic.in/PDF/coastal%20data.pdf
  • Chadha, S and Sekar, KC (1999) Bhitarkanika:myth and reality Nataraj publishers, Dehra Dun Available at - NIO, Goa
  • Padmanaban P and Dinesh K.P (2011) A checklist of Marine Mammals of India Marine Biology Reginal centre, Zoological Survey of India 4pp Available at - http://zsi.gov.in/checklist/Marine%20mammals%20of%20India.pdf
  • Jefferson, TA; Leatherwood, S and Webber, MA (2006) Marine mammals of the world World biodiversity database Available at - http://nlbif.eti.uva.nl/bis/marine_mammals.php?menuentry=inleiding

Page last updated on:2012-11-07

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