The Rare Dolphin

We don’t always think of dolphins as being a rare species; however, the Chinese River Dolphin is considered by scientists to be the rarest of all marine mammals, to the point of possibly being extinct.

This rare dolphin makes its home in the freshwater of the Yangtze River. Its low dorsal fin and light color have given it the alternate name of “white-flag dolphin.” As with other species of river dolphins, it originally came from the ocean.

Decreasing numbers have made this species of dolphin difficult to research and study. The dolphins are shy and do not expose much of themselves when surfacing for air. They feed mostly on freshwater fish. Due to the murky waters of the Yangtze, they rely on sound for feeding, orientation, and communication. Based on studies of similar species, scientists think the Chinese River Dolphin uses two main types of sounds: clicks and whistles. They use the clicks for navigation and identifying prey. Whistles are used for communication.

Currently, its habitat is limited to the Yangtze River in China. Habitat loss due to development along the river has further reduced its range. River development includes the construction of dams and other water management devices along the river. This affects the dolphins’ movements within the river ecosystem. Fish resources have also declined.

Reserves have been established for the preservation of the species. However, these attempts do not prevent accidental deaths. Little, if any, effort has been made to breed the dolphins in captivity.

A survey team conducted an extensive study in 2006 using visual and acoustic measures. They failed to locate any individual animals within the species’ range. The National Marine Fisheries Service has concluded that the Chinese River Dolphin may now be extinct.