Scientific name: Pontoporia blainvileii (The fransiscana is a very hard dolphin to classify, (the reasons for this are discussed with the information on range) and it has had at least three different scientific names: Delphinus blainvilleii, Pontoporia tenuirostris, and Stenodelphis blainvillei. If you see any of those names in an old book, you'll know what they mean.)

Other names: La Plata River Dolphin

Anatomy: Fransiscanas are more slender and less "chunky" looking than other species of river dolphins, and their rostrums are proportionally longer. They have between 200 and 246 teeth, with 50 to 60 in each of the four jaw bones. Their eyesight is better than that in other species of river dolphins. There is a visible constriction at the neck where it can be bent, like in other river dolphins. Their neck vertebrae, as is usual in river dolphins, are not connected. Their dorsal fins are triangular and pointed, and extend into a low keel to their flukes, which are very large. Pectoral fins are also large, and finger bones are visible through the skin. Their skin color is usually brownish in the young dolphins, and grayish in the adults. Young dolphins also have shorter rostrums than the adults do. Fransiscanas are very small, measuring only about 5 or 6 feet in length. The dolphins in the northern reaches of their range are smaller than those in the south. Male fransiscanas weigh less than the females, usually about 95 pounds. Females weigh about 115 pounds.

Range: Fransiscanas are the only river dolphins that do not actually enter/live in rivers. They live in the estuary of Rio de la Plata and in the coastal waters of the Atlantic coast of South America, from Baia de Santos (Brazil) to Golfo San Matias (Argentina). In the winter seasons they leave the estuary and travel north along the coasts of Brazil and Uruguay. The fact that these dolphins do not enter the river has caused much confusion. After being classified as oceanic dolphins, they were put into the river dolphin family due to their anatomy, which is much more like river dolphins than oceanic dolphins.

Behavior: We know very little about the behavior of Fransiscanas. These dolphins are slightly shy, but will approach small boats, and they usually swim at speeds of 5 to 7 miles per hour. Their young are born in October through January. They usually travel in pods of 4 or 5. They can live for about 15 years, but usually less due to environmental threats.

Environmental status: Gill nets in Argentina, Uruguay, and Brazil kill many Fransiscanas each year.

Food: Fransiscanas eat mainly mullet, shrimp, and squid.


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