Yangtze finless porpoise. A small coastal cetacean lacking a dorsal fin and possessing a long, low ridge, inhabiting shallow waters such as the coasts of East Asia, the coast of Honshu in Japan, and along the Yangtze River. Body length is 1.6–1.9 m and weight is 40–70 kg. It feeds on fish, squid, and crustaceans, and usually occurs alone or in small groups of a few individuals. It forages using echolocation and exhibits relatively little surface behavior. Calving interval is 1–2 years and gestation lasts about 11 months. Population is in decline and it is listed as Critically Endangered (IUCN category 1B).