Sousa chinensis
Indo-Pacific humpbacked dolphin

Indo-Pacific humpbacked dolphins, Sousa chinensis, are found in the Indian and Pacific Oceans. They are found in the Eastern hemisphere along the coasts of Asia, east Africa, and Australia. (Carwardine 1995) (Carwardine, 1995; van der Toorn, 1999)

Sousa chinensis occurs in coastal waters. Their distribution coincides with the distribution of coastal mangrove areas in the Indian and Pacific Oceans. This dolphin is usually found in shallow waters that are less than 20 meters in depth. This species prefers to swim in warm waters ranging from 15 to 36 degrees Celsius. (van der Toorn, 1999)

Indo-Pacific humpbacked dolphins range from 220 to 230 cm in length, females may be slightly smaller. They can be characterized by a sloping "forehead" and a double-step dorsal fin characterized by a smaller fin that sits on an elongated hump on the dolphin's back. The beak is long and slender, usually exposed when surfacing. When diving the back is strongly arched. Color can vary greatly between different populations, ages, and individuals. Coloration is typically light gray or a lighter shade of blue. Calves are typically darker than adults. The underside is speckled and lighter colored than the dorsal surface. Each of the jaws of Sousa chinensis contains 29-38 pairs of peg-like teeth. (Carwardine, 1995; Ellis, 1982)

Indo-Pacific humpbacked dolphins are gregarious animals. They typically live in groups of 3 to 7 but groups of up to 20 have been observed. These dolphins have been known to chase off and kill sharks. Indo-Pacific humpacked dolphins are considered slow swimmers, moving an average of 4.8 km/hr. They surface for long intervals of between 40 and 60 seconds. Aggression appears to serve a useful purpose in predator defense and in a social context as more aggressive individuals often achieve higher dominance rank. (Evans, 1987; van der Toorn, 1999)

Sousa chinensis feed in shallow waters on fish, mollusks, and crustaceans. When searching for food they use echolocation and hunt in small groups. They have been known to hunt singly. They tend to feed independently whether they hunt singly or in groups, this may reflect on the density of their prey and the schooling behavior of the dolphins themselves. Although gregarious, these dolphins can be aggressive and require some distance separating themselves from others when feeding. (Evans, 1987; May, 1990)

No known negative effects.

This species is occasionally hunted for meat, but not on a commercial scale. A few individuals have been captured alive for display at marine parks. One population of a related species on the west coast of Africa actually cooperate with local fishermen. (van der Toorn, 1999)

Destruction of coastal mangrove habitats throughout Asia is believed to be causing a decline in the numbers of Indo-Pacific humpbacked dolphins (May 1990). (May, 1990)

There are no major physical differences between Indo-Pacific humpbacked dolphins and Atlantic humpbacked dolphins. It appears that the two species of dolphin are closely related, being only geographically isolated. Some scientists, however, divide the genus Sousa into five distinct species. In this arrangement S. teuszii, the Atlantic humpbacked dolphin remains intact, but S. chinensis is divided split into 4 species: S. plumbea, S. lentiginosa, S. chinensis, and S. borneensis. (Carwardine, 1995; Ellis, 1982; May, 1990)