求江豚的介绍，要英文的～单词不要太深～我高一～

江豚 Neophocaena phocaenoides (Finless porpoise)
Finless porpoises are widely distributed in the coastal waters of Asia, from the Persian Gulf, east and north to Central Japan and as far south as the northern coast of Java and the Strait of Sunda (see map). Finless porpoises are described as a coastal, estuarine or riverine species and they are usually sighted near the coast.

Natural History
Finless porpoises are slender and have no dorsal fin. In its place along the mid-dorsum is a low dorsal ridge which is covered by thick denticulated skin. Newborn finless porpoises are mainly black with some grey on the dorsal ridge area. These young porpoises quickly become lighter and after 4 to 6 months attain the uniform light grey colour of adults. Both male and female finless porpoises grow to lengths greater then 1.55 m. Although there is a great deal of variability between populations of finless porpoises, males become sexually mature at 4.5 - 9 years and females at 3