Tucuxi and Guiana Dolphin: Sotalia fluviatilis and S. guianensis

Abstract

This chapter explores the two species of the genus Sotalia, riverine Sotalia fluviatilis and marine S. guianensis. The two Sotalia species are very similar in coloration, differing mainly in body size and number of teeth, and somewhat resembling a small bottlenose dolphin, Tursiops. They are light gray to bluish gray on the back and pinkish to light gray ventrally, with a distinct line from the mouth gape to the flipper's leading edge. There is a lighter area on the flank between the flippers and the dorsal fin and another mid-body at the level of the anus. The marine species has another light gray rounded streak on both sides of the caudal peduncle. In both species, the eyes are large, and there is black countershading around the eyes. Sotalia dolphins show a variety of aerial behaviors such as full leaps, somersaults, fluke-ups, spy-hopping, surface rolling, and porpoising. In coastal areas, feeding and traveling are by far the most common behaviors, although resting and milling are rare. Socializing involves various tactile contacts, and herding of females by males has been occasionally seen in southern Brazil. Bow-riding has not been recorded, but Guiana dolphins may surf in waves and wakes produced by passing boats. © 2009 Copyright © 2009 Elsevier Inc. All rights reserved.