Sotalia fluviatilis (Gervais & Deville, 1853)

Scientific Name and Size

The tucuxi, scientifically named Sotalia fluviatilis (Gervais & Deville, 1853), is frequently described as looking similar to the bottlenose dolphin, but it is typically smaller, reaching around 1.5 m (4.9 ft) in length.

Body Coloration

Its back and sides are colored light to bluish grey, while its ventral region is much lighter and often pinkish. It is theorized that this pinkish color may be caused or intensified by increased blood flow.

Morphological Features

The dorsal fluke is typically slightly hooked, the beak is well-defined and of moderate length, and there are 26 to 36 pairs of teeth in both the upper and lower jaws. The tucuxi has one of the largest known encephalization quotients among mammals.

Core Distribution Range

The tucuxi lives along much of the length of the Amazon River and many of its tributaries, and is found in Venezuela, Brazil, Peru, Ecuador, and southeastern Colombia. Numerous individuals have been seen in the Orinoco River further north, though it is not clear whether these are tucuxi or costero.

Expanded Range Observations

This species has recently been found to inhabit a larger range, including the northeast portion of Brazil such as the state of Amapa, which covers more basins than just the Amazon basin. This species occurs only in freshwater habitats.

Habitat Threat Overview

The tucuxi's habitat has been greatly affected by human-caused activities. The expansion of hydroelectric projects has often led to population isolation when dams are built.

Pollution Impacts

Human-caused pollution has also degraded habitat quality and increases the chance that tucuxis will consume heavy metals.

Feeding Behavior

Tucuxis forage in tight groups, often chasing fish in rapid dashes just below the water surface, which causes fish to jump out of their way. Thirty species of fish are known to be their prey; some of these fish live in protected lakes and channels, while others live in fast-flowing rivers.

Traditional Medicine Uses

In local traditional medicine, oil and fat from the tucuxi's skin is made into an ointment that is rubbed on wounds or sore body parts. This ointment is thought to treat illnesses such as hemorrhoids, rheumatism, and arthritis, while ground tucuxi teeth are used as a powder to treat asthma.

Magical Charm Uses

Throughout Northern Brazil, tucuxi eyes, teeth, and genital organs are sold as magical charms said to bring good luck, love, and financial gain. Baths made with these body parts are claimed to help people attract sexual partners when one bathes in the prepared water.

Aphrodisiac Products

Other products, such as perfumes and powders made with tucuxi genital organs, are sold as aphrodisiacs.

Harvest Impact Uncertainty

The number of tucuxis harvested for magical or religious purposes, and the impact of this harvest on tucuxi populations, remains unknown.