Indo-Pacific humpback dolphin (Sousa chinensis)

Indo-Pacific humpback dolphin fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Indo-Pacific humpback dolphin description

The Indo-Pacific humpback dolphin has a typically streamlined body and a long slender beak ⁽⁵⁾. Populations differ in both shape and colour, with those in the west of the range possessing a 'double-step' dorsal fin with a fatty hump upon which the dorsal fin sits ⁽⁶⁾. Although usually dark grey on their back and lighter underneath, white and pink variations are also known; the most famous of these are the 'pink dolphins' of Hong Kong bay ⁽²⁾. The humpback dolphin has an unusual diving posture, first lifting its beak out of the water and arching its back, and then pausing before dipping below the surface or flipping its tail to dive ⁽²⁾. Given the wide morphological differences, there is some disagreement as to whether the Indo-Pacific humpback dolphin does in fact represent four different species: Sousa plumbea, Sousa lentiginosa, Sousa chinensis and Sousaborneensis respectively ⁽⁵⁾.

French

Dauphin À Bosse De L'Indo-pacifique.

Spanish

Bufeo Asiático, Delfín Blanco De China.

Size

Male length: up to 3.2 m ⁽²⁾

Female length: up to 2.4 m ⁽²⁾

Weight

150 - 200 kg ⁽²⁾

Indo-Pacific humpback dolphin biology

Little is known about the behaviour of the Indo-Pacific humpback dolphin, but small groups of around three to seven individuals are most commonly seen ⁽⁵⁾. These are slow-swimming dolphins, typically travelling at around 4.8 kilometres per hour ⁽⁵⁾. Despite this sluggishness, many aerial displays are seen; including breaching, when the dolphin leaps out of the water, lob tailing (slapping the surface of the water with the tail) and spyhopping, when the dolphin raises its head vertically out of the water and then sinks below the surface quietly ⁽⁶⁾. These dolphins feed primarily on reef-associated and estuarine fish ⁽⁹⁾. Individuals may be aggressive and this appears to affect dominance rank within the group ⁽⁵⁾.

Indo-Pacific humpback dolphin range

Found along the coasts of the Indian and western Pacific Oceans ⁽⁶⁾, from southern China and north Australia in the east, to South Africa in the west.

See this species on Google Earth.

Indo-Pacific humpback dolphin habitat

Inhabits coastal tropical and subtropical waters, preferring areas that are less than 20 metres deep ⁽⁶⁾.

Indo-Pacific humpback dolphin status

Classified as Near Threatened (NT) on the IUCN Red List ⁽¹⁾, and listed on Appendix I of CITES ⁽⁴⁾.

Indo-Pacific humpback dolphin threats

Indo-Pacific humpback dolphins are at risk from factors that also threaten all other cetaceans, such as entanglement in fishing nets, pollution and the depletion of fish stocks worldwide ⁽⁶⁾. These coastal dolphins are also threatened by boat traffic, a factor that is especially pertinent in Hong Kong where this dolphin's habitat is also the busiest harbour in the world. In South Africa, shark nets may be an important cause of mortality but more data on this potential threat is required ⁽⁸⁾.

Indo-Pacific humpback dolphin conservation

Information on population densities and distributions are urgently needed before an effective conservation plan can be put into action.

Environment Agency - Abu Dhabi is a principal sponsor of ARKive. EAD is working to protect and conserve the environment as well as promoting sustainable development in the Emirate of Abu Dhabi.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

To help conserve dolphins visit:

• Whale and Dolphin Conservation Society:
  www.wdcs.org

Authentication

Authenticated (20/8/02) by Shanan Atkins. Richards Bay Humpback Dolphins.
http://www.dolphins.org.za

Glossary

Beak

In cetacea (whales and dolphins), the elongated forward part of the head, comprising the lower jaw and upper jaw or 'rostrum'.

Cetaceans

A group comprising all whale species; therefore including dolphins and porpoises.

Dorsal fin

In fish, the unpaired fin found on the back of the body.

References

1. IUCN Red List (November, 2008)
   http://www.iucnredlist.org
2. Carwardine, M., Hoyt, E., Fordyce, R.E. and Gill, P. (1998) Whales and Dolphins. HarperCollins Publishers, London.
3. CITES (July, 2002)
   http://www.cites.org
4. Animal Diversity Web (July, 2002)
   http://animaldiversity.ummz.umich.edu/accounts/sousa/s._chinensis$narrative.html
5. Whale and Dolphin Conservation Society (July, 2002)
   http://www.wdcs.org
6. Atkins, S. (2002) Pers. comm.
7. Richards Bay Humpback Dolphins (July, 2002)
   http://www.dolphins.org.za/