The Mekong (Irrawaddy) Dolphins
(Orcaella brevirostris)
Photo: Ian Baird
" Once upon a time, a beautiful maiden forced by her parents to marry a slimy python leapt into the Mekong River. But her suicide bid failed. She was transformed into a dolphin."
DENIS D. GRAY / Associated Press Writer
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Introduction |
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Mekong (Irrawaddy) dolphin |
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Photo Galleries |
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Maps |
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Distribution in the Mekong River |
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About me |
Description
Common Name:
Irrawaddy dolphin
Latin Name:
Orcaella brevirostris
Other Names:
Snubfin dolphin, Loma Hua Baht (Songkha Lake, Thailand), Pa Ka (Laos)
Primary Classification:
Odontocete (Toothed whale, dolphin or porpoise)
Sub Classification:
Delphinidae
Description:
The Irrawaddy dolphin has a rounded head with no beak, and a flexible
neck. They can vary in colour from dark and light blue- grey, to pale
blue. It is grouped as an oceanic dolphin, although some dolphins may live
in the freshwater of rivers all their life (such as the Ganges in India).
This species of dolphin has a small triangular shaped dorsal fin with a
rounded tip, below the centre of the back , and is a slow swimmer -
usually moving in small groups. Irrawaddy dolphins are very similar to the
shape of the Beluga (toothed whale), and to the shape of the Finless
Porpoise with its blunt round head, so they are sometimes difficult to
tell apart. They can have up to 40 teeth on their upper jaw, and 36 teeth
on the lower jaw.
Field ID:
Streamlined body, Round melon, Flexible neck, No prominent beak, Single
blowhole, Long, broad, spatulate flippers, Blue-grey skin colour, Normally
in small groups, Shy and retiring by nature
Length (metres):
Adult Irrawaddy dolphins can grow between 2.1 and 2.6 metres long.
New-born are about 1m in length.
Weight:
A fully grown Irrawaddy dolphin can weigh between 90 and 150 kg. Birth
weight is about 12kg or so.
Diet:
Fish, crustaceans and squid
Behaviour:
The Irrawaddy dolphins usually swim in groups of six, or less. They rarely
show themselves above the surface of the water, but sometimes may make low
horizontal leaps. They may also do something called 'spyhopping', which is
the name given to the activity of poking their heads out of the water -
perhaps to have a good look around! They have also been seen to spit out
water from their mouths whilst spy-hopping! The Irrawaddy dolphin species
do not ride the waters infront of the bows of boats, but they do have a
special relationship with fisherman on the Irrawaddy and Mekong rivers, by
driving fish into their nets.
source: WDCS