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.
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.