Ganges River Dolphin

Platanista gangetica gangetica

Order - Cetacea

Family – Platanistidae 

Taxonomy:

The Ganges River dolphin and the Indus River dolphin were previously treated as separate species, but have recently been reduced to subspecies of a single species, Platanista gangetica (IUCN, 2003a, Reeves 2004).  Both subspecies are listed as Endangered Species on the IUCN Redlist, with an estimated wild population of only 3000 individuals. 

 Distribution and habitat: 

P. gangetica is found in India, Nepal, Bhutan and Bangledesh.  It lives in the muddy waters of the Ganges, Brahmaptura, Meghna, Karnaphuli and Hoogly river systems.  It is found only in fresh water, however it migrantes locally to tidal waters during the monsoon season. 

 Size:  Average size for P. gangetica is between 1.5-2.5m (4.9-8.2 ft) and weighs up to 90 kg (200 lbs

 Characteristics:                                 

The Ganges River dolphin has a long, beaked rostrum that exposes large teeth near the front and an upwardly curving mouth.  The body is stocky with paddle-shaped flippers and is countershaded steel grey to black on the dorsal side with a lighter colored underside.  The dolphin has no dorsal fin, but instead has a short, triangular hump.  The most notable features are the dolphin's tiny, poor-seeing eyes, which lack a crystalline lens, so they are effectively blind.  Their eyes can do little more than recognize dark and light.  It is theorized that the lack of eyesight in P. gangetica is related to its habitat, which is very murky making eyesight virtually useless.

 Feeding

P. gangetica feed on several species of freshwater fish and invertebrates, sometimes taking waterfowl, too.  Because these dolphins are basically blind, they rely on sophisticated echolocation techniques tofind food and navigate.  In addition to echolocation, P. gangetica swim on one side along the floor of the riverbed, dragging its flipper and snout through the muddy substrate.  The physical touch of flipper and snout along the muddy floor of the riverbed give the dolphin information about surrounding and the whereabouts of prey 

Conservation Status

The Ganges River dolphin lives in one of the world's most densely populated areas, home to almost 1/10 of the world's population.  The rivers are frequently dammed for electricity and irrigation, habitat destruction is making prey scarce and pollution is ever increasing.  P. Gangetica is hunted for meat and its oil which is used for lamp fuel.

 References:

Animal Diversity Web

http://animaldiversity.ummz.umich.edu/site/accounts/information/Platanista_gangetica.html

Animal Info – Ganges River dolphin

http://www.animalinfo.org/species/cetacean/platgang.htm

Cetacea: Platanista gangetica

http://www.cetacea.org/ganges.htm