is found in the coastal waters and rivers of Southeast Asia. It is concentrated in the eastern IndoPacific region. can be found from Pakistan to Korea, Japan, Borneo and Java. (Gaskin 1982, Nowak 1991)
lives in both fresh and salt water habitats. It is found in shallow coastal waters such as the Sea of Japan as well as fresh water rivers like the Yangtze river in China. is occasionaly found in inland lakes which have been cut off from the ocean but are still salt water. seems to prefer rocky promonotories and strong currents (Ganslosser 1988).
is sometimes called the Black Finless Porpoise because of the common misconception that its skin is black. In reality, the upper portions of are gray with touches of blue on the back and sides. The ventral parts are paler. Pale spots do however decrease with age, and the skin turns black immediately after death. Further, the skin coloring differs from pale in oceanic and brackish waters, to almost black in rivers. has no dorsal fin but has instead has a midline dorsal ridge. This ridge contains horny papillae. is the smallest cetacean and grows to only 150-190cm. It has a distinct eel-like shape due to its lack of dorsal fin and round, beakless head. The jaw of contains 15-21 spade shaped teeth on each side of the upper and lower jaw. (Ganslosser 1988, Herman 1980, Nowak 1991)
reaches sexual maturity by the age of 2. Reproductive cycles differ among geographic groups such as those located near Japan and those near China. The breeding cycle is 1-2 years and gestation lasts between 10 and 11 months. Births occur between February and August and there is usually 1 young per birth. Newborns are around 25kg and are weaned between September and June. has been found to live up to 23 years. (Bryden & Harrison 1986, Nowak 1991).
Mothers carry their offspring on a patch of skin on the dorsal surface which is covered with horny papillae. This acts like a saddle on which the young can attach and be carried. Although obviously for carrying young, the horny papillae contain nerve endings and may be a means of auxillary orientation. This "extra" means of orientation could be very beneficial tosince it often lives in murky waters.
is a relatively slow animal. It rolls to the surface to breath and is rarely observed jumping out of the water. Maximum dives last up to 11-15 seconds. It forms mostly small schools and is rarely seen in groups of more than 4. More often, is solitary or in mother-offspring groups. Some of the groups of (mainly the Japanese groups) are migratory. They frequent the Inland Sea during the spring and migrate to the Pacific coast from late summer to midwinter. (Gaskin 1982, Ganslosser 1988, Nowak 1991)
feeds mainly in the euphotic zone. It eats benthic invertebrates, cephalopods such as squid, and small demersal fish. is a very aggresive hunter, and fish have been observed jumping out of the water when chased by it (Bryden & Harrison 1986). (Gaskin 1982)
is hunted by humans for its meat, skin and oil (Nowak 1991).
Althoughis not endangered, there are many threats to its survival as individuals if not as a species. is effected by pollution as well as bottom dredging. It is also killed by motor boat collisions, hunters, fish and shrimp nets, and its natural predator, the shark. (Bryden & Harrison 1986, Nowak 1991)
appears to be very adaptable and is found in habitats which other species have abandoned. These include the Tung-Ting Lake in China, which is landlocked and extremely shallow. However, isn't as quick to adapt to human ways. They tend to eat objects off the river bottom, including things as detrimental to their health as bottle caps thrown in the water by humans; these appear to be a major cause of death (Bryden & Harrison 1986).
Lindasy DuVall (author), University of Michigan-Ann Arbor.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
found in the oriental region of the world. In other words, India and southeast Asia.
an animal that mainly eats fish
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
Bryden, M. and Harrison, R. 1986. Research on Dolphins. Clarendon Press, Oxford.
Ganslosser, U. 1988. Grizimek's Encyclopedia. McGraw-Hill Publishing, New York. Vol 4. pgs. 386, 414-415.
Gaskin, D.E. 1982. The Ecology of Whales and Dolphins. Heinemann, London. pgs. 3, 127, 229, 235.
Herman, L. 1980. Cetacean Behavior. John Wiley and Sons, New York. pg 268.
Nowak, R.M. 1991. Walker's Mammals of the World. Johns Hopkin's University Press, Baltimore. Vol 2. pgs. 1005-1006.