Tucuxi
Sotalia fluviatilis

Found both along the coast of South America and in the Amazon River basin, Tucuxi, pronounced "too-koo-shee", is the only oceanic dolphin species that inhabits a major river system to a significant extent. It is one of the smallest cetaceans, with a length of around 1.7-1.8 meters. Up to five separate species have been proposed by taxonomists. Coloration varies significantly from species to species. The dorsal side may range from blue and gray to black and brown, while the ventral side can be white, pink, or violet gray. The dorsal fin is of the same color as the back except for an area of yellow on each side near the top. The beak is relatively long, and the forehead slopes gently. Unlike members of the closely related genus Sousa, there is no hump on Tucuxi's back. The dorsal fin is low and has a broad based. Tucuxi is a slow swimmer and usually aggregates in groups of between 8 and 20 individuals. Rarely does it jump clear of the water. It is, however, more active than the Boto. It is threatened by the hydroelectic dams on the Amazon River, which break up the estuarine and riverine populations into isolated units. The fish that used to migrate between these areas are now extinct.

Bibliography

Baker, Mary L. Whales, Dolphins, and Porpoises of the World. New York: Doubleday & Company, Inc., 1987.

Carwardine, Mark. Eyewitness Handbooks: Whales, Dolphins, and Porpoises. New York: Dorling Kindersley Ltd., 1995.

Ellis, Richard. Dolphins and Porpoises. New York: Alfred & Knopf, Inc., 1982.

Klinowska, Margaret. Dolphins, Porpoises, and Whales of the World: The IUCN Red Data Book. Gland, Switzerland: World Conservation Union, 1991.