Baiji

Scientific Classification

Common Name

baiji, Yangtze River dolphin

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Cetacea

Suborder

Odontoceti

Family

Platanistidae

Genus Species

Lipotes vexillifer

Fast Facts

Description

Baijis have a fusiform body with a small head, tiny eyes, prominent melon and a long, narrow beak that is slightly up-curved at the tip. The dorsal fin of the baiji is low and triangular and the flippers are broad and rounded. The dorsal portion of the body is gray with whitish streaks from the ventral area extending into the face and head region.
Female: Females are slightly larger than males.

Size

Male: maximum 2.29 m (7 ft. 6 in.)
Female: maximum 2.53 m (8 ft. 4 in.)

Weight

Male: 130 kg (290 lbs.)
Female: 170 kg (370 lbs.) larger individuals may weigh up to 227 kg (500 lbs.).

Diet

Small fish;will feed on fish at surface and along bottom.

Gestation

10 to 11 months. The interbirth interval is 2 years. There is a single young at birth.

Sexual Maturity

More than 6 years in females; approximately 4 years in males

Life Span

Based on dentition, a wild individual was estimated to have lived 24 years.

Range

Currently only found in the Yangtze River of China. Historically, the Baiji was also found in Dongting and Poyang Lakes.

Habitat

Freshwater riverine habitat

Population

Before 1900, there was a population around 3,000 to 5,000 individuals. Now there may be less than 10 and possibly extinct.

Status 

IUCN: Critically Endangered (possibly extinct)
CITES: Appendix I
USFWS: Endangered

Fun Facts

1. Scientists have placed the baiji in the family Platanistidae, the river dolphin family. Four other species of river dolphins also are in this family. They are:
   - boto (Amazon river dolphin) Inia geoffrensis, South America
   - franciscana (La Plata river dolphin) Pontoporia blainvillei, South America
   - Ganges susu (Ganges river dolphin) Platanista gangetica, India
   - Indus susu (Indus river dolphin) Platanista minor, Pakistan
2. Baiji is a Chinese word meaning "a white dolphin." This species is one of the most endangered cetaceans in the world, with a population numbering in the tens or fewer.
3. Females are slightly larger than males.

Ecology and Conservation

Little is known about a river dolphin's natural history. However, several species are in danger of extinction. Threats to river dolphin populations include pollution, subsistence hunting, industrial development, dam construction, riverbank deforestation, over fishing, and incidental capture in commercial fisheries.

Why is the baiji endangered? Varying water levels in the Yangtze River due to industrial development have limited available habitat. Over fishing has decreased the baiji's food supply. Pollution harms both the dolphins and their prey. Baiji may be injured or killed by explosions during construction, and by boat propellers.

Baiji may also be caught and killed by illegal fishing devices called rolling hooks. These long, braided lines with numerous sharp hooks are meant to catch fishes. However, baiji also may become ensnared in the mass of hooks. Others become entangled in stake net traps.

The baiji has been protected by China since 1975. Chinese biologists began devising a protection strategy in 1986.By establishing reserve sites along the Yangtze River, scientists are hopeful that the species can be saved. The Baiji has been listed as Critically Endangered since 2006 and the population is still declining and may be extinct.

Bibliography

Jefferson, T.J. Leatherwood, S. and M.A. Webber. FAO Species Identification Guide: Marine Mammals of the World. Rome. FAO, 1993.

Leatherwood, Stephen, and Reeves, Randall R. The Sierra Club Handbook of Whales and Dolphins. San Francisco: Sierra Club Books, 1983.

Nowak, Ronald M. (ed.). Walker's Mammals of the World. Vol. II. Baltimore: Johns Hopkins University Press, 1991.

Parker, S. (ed.). Grizmek's Encyclopedia of Mammals. Vol. IV. New York: McGraw-Hill Publishing Co., 1990.

Reeves, R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell (Peter Folkens illustrator).National Audubon Society: Guide to Marine Mammals of the World. New York: Random House, 2002.

Smith, B.D., Wang, D., Braulik, G.T., Reeves, R., Zhou, K., Barlow, J. & Pitman, R.L. 2017. Lipotes vexillifer. The IUCN Red List of Threatened Species 2017: e.T12119A50362206.

University of Michigan – Zoology Department – Animal Diversity Web
http://animaldiversity.ummz.umich.edu

IWC. 2000. Report of the Standing Sub-Committee on Small Cetaceans. IWC/52/4. 52nd Meeting of the International Whaling Commission, Adelaide, Australia. Downloaded on 24 September 2018.

Smith, B.D., Wang, D., Braulik, G.T., Reeves, R., Zhou, K., Barlow, J. & Pitman, R.L. 2017. Lipotes vexillifer. The IUCN Red List of Threatened Species 2017: e.T12119A50362206. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T12119A50362206.en.Downloaded on 24 September 2018.