Description
Common Name:
Fraser's dolphin
Latin Name:
Lagenodelphis hosei
Other Names:
Sarawak dolphin, Shortsnout dolphin, Bornean dolphin, Fraser's porpoise, White-bellied
dolphin
Primary Classification:
Odontocete (Toothed whale, dolphin or porpoise)
Sub Classification:Delphinidae
Description:
Fraser's dolphin calves are born with dull coloration, but as they mature
into adult animals they develop a more striking appearance. The adult dolphins
have blue-grey upper sides, and are creamy white or pink on their belly and
throat. Some of them, especially the males, have a vivid dark black lateral
body stripe; the width and intensity of the stripe is thought to increase
with age. They also have a dark blue/ grey line (or lines) running from their
beak to their flippers.
These dolphins have small pointed flippers and a small dorsal fin in relation
to their body size. They have a well-defined but short beak.
Field ID:
Stocky body, Blue-grey skin colour, Dark lateral stripe, Small fin, Short,
defined beak, Small, narrow flippers
Length (metres):
New-born Fraser's dolphins are about 1 metre (39in) long, and adults are between
2 and 2.6 metres (6ft 6in - 8ft 6in) long.
Weight:
When they are born they weigh approximately 19 kg (40lb), and when fully grown
they weigh between 160 and 210 kg (350 - 460 lb).
Diet:Fish, crustaceans squid
Behaviour:
Fraser's dolphins are sociable animals. They are often seen in big groups
of 100-500 animals and frequently with other cetaceans. They are deep divers,
going to depths of at least 250 - 500m.
They have an aggressive swimming style and are not normally playful. In most
areas they are wary of boats, but have been seen riding bow waves off Natal
in South Africa, and in the Philippines.
Distribution:
The distribution of the Fraser's dolphin is not very well known. However they
are mainly seen in deep, tropical waters. They seem relatively rare in the
Atlantic Ocean and may range across the Indian Ocean, although sightings have
only been confirmed in waters off South Africa, Sri Lanka and Indonesia. They
also occur away from the equator as far north as Taiwan and Japan and, in
small numbers, off Australia.
Population Size:Unknown
Threats:Hunting, entanglement in fishing nets, environmental changes
This is a distinctive dolphin, with a stocky body and extremely small appendages. The short dorsal fin is triangular or slightly falcate, and tends to be more erect in adult males. There is a stubby but well-defined beak. The color pattern is striking; the most distinctive feature is a dark band of varying thickness, running from the face to the anus (in some regions, the band is indistinct). This band is scarcely apparent on young animals, appearing to widen and darken with age, especially in adult males. There is also a flipper stripe that starts mid-length along the lower jaw (in some animals the side stripe is so wide that it merges with the flipper stripe, creating a dark face mask).
References:
Whales Dolphins and Porpoises, Mark Carwardine, Dorling Kindersley Handbooks.
National Audubon Society Guide to Marine Mammals of the World, Reeves, Stewart,
Clapham and Powell.