Fig 1
Fig 2
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Order : CETARTIODACTYLA
Infraorder : Cetacea
Family : Delphinidae
Species : Stenella longirostris
Total Length : up to 2.2m
Weight : up to 95 kg
Stenella longirostris
(Long-snouted Spinner
Dolphin, or more simply the Spinner Dolphin), is a
widespread species of the world's tropical seas and oceans.
This is a small marine mammal reaching up to just 2.2 metres in length. Its identifying feature
is the long, dark, narrow snout which ends in a black tip. Playful in nature, it may be encountered
riding the bow waves of powered motorboats.
Its patterning is variable, but Southeast Asia populations tend to have medium
grey upperparts, pale grey flanks and white underparts. Some populations,
however, may be all dark grey.
Spinner dolphins are so called on account of their acrobatic agility - they
are able to spin around on their axis as they leap above the water's surface.
They may typically be encountered in pods of around 10-20, but sometimes in
groups of over 100
individuals. They feed mainly on small fish, squid and prawns. Dolphins are
communicative mammals, which rely on echolocation to accurately locate their
food prey.
Spinner dolphins prefer deep, clear water; in Southeast Asia they are more
likely to be found in oceanic waters away from the shallow Sunda Shelf e.g.
Eastern Indonesia and the Philippines. The somewhat smaller spinner dolphins
found in the shallow seas of Western Indonesia, the South China Sea and the Gulf
of Thailand are considered a different subspecies - Stenella longirostris
roseiventris.
Figs 1 and 2 : This pair of Long-snouted Spinner Dolphin were sighted off Manado,
North Sulawesi, Indonesia.
Fig 3 : A deep ocean trench, rich in marine life, lies between the city of
Manado, North Sulawesi, Indonesia and the islands of Manado Tua (centre) and
low-lying Bunaken (right).
References :
Payne, J., Francis, C.M., 1998. A Field Guide to the Mammals of
Borneo. The Sabah Society.
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