The dorsal fin of the Indo-Pacific Humpbacked dolphin, Sousa
chinensis, usually sits on a distictive hump, as here. Eastern
populations may have little hump at all, and may even be a separate
species. This dolphin, semi-captive in Singapore, is more pale pink and
speckled than most, and, along with the shape of the dorsal fin, could
be quite old. Other dolphins can be mixes of light gray and brown, and
the young "Sousas" generally have more curved dorsal fins.
The "Sousa" is about the size of the bottlenose dolphin,
but looks and swims quite differently. They surface with their heads up,
like this, and may show their flukes as they dive. They prefer to swim
slowly in water less than 65 feet deep, and do not seem to be attracted
to boats. They may have learned that boats are dangerous in much of
their near shore range from Australia to Africa.