Finless Porpoiseスナメリ

Species Data

Classification

Cetartiodactyla / Phocoenidae Source

Distribution

Finless porpoises inhabit coastal waters of East and South Asia, from the Persian Gulf through the Taiwan Strait to the Yellow Sea and Japan, with a distinct freshwater population in China's Yangtze River that is critically endangered. Source

Did You Know?

• Lacking a long spinous process just behind the skull, finless porpoises can rotate their heads through a wide range of roughly 40 degrees. Source
• In 1976, Toba Aquarium in Mie Prefecture, Japan, achieved the world's first successful captive breeding of the finless porpoise. Source
• Genetic evidence indicates that Neophocaena represents the most basal living lineage within the porpoise family, making it evolutionarily significant among cetaceans. Source

FAQ

Why doesn't the finless porpoise have a dorsal fin?

Instead of a true dorsal fin, it has a low ridge covered in thick skin with rows of tiny tubercles, an adaptation whose exact function is still studied by researchers. Source

Where can finless porpoises be found in Japan?

They occur in coastal waters from Sendai Bay in the north down to Tokyo Bay, Ise Bay, the Seto Inland Sea, and the coast of Nagasaki Prefecture, including Omura Bay and the Ariake Sea. Source

Is the finless porpoise endangered?

The species is classified as Endangered by the IUCN. Its most critical population lives in China's Yangtze River, where only about 1,249 individuals were estimated to remain in 2023. Source