Pontoporiidae
| La Plata dolphin | |
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| Skeleton in the collection of Museo di storia naturale e del territorio dell'Università di Pisa | |
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| Size compared to an average human | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Synapsida |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Clade: | Delphinida |
| Superfamily: | Inioidea |
| Family: |
Pontoporiidae Gray, 1870 |
| Genus: |
Pontoporia Gray, 1846 |
| Species: | P. blainvillei |
| Binomial name | |
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Pontoporia blainvillei Gervais & d'Orbigny, 1844 |
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| La Plata dolphin range | |
The La Plata dolphin or Franciscana (Pontoporia blainvillei) is found in coastal Atlantic waters of southeastern South America. It is a member of the river dolphin group and the only one that actually lives in the ocean and saltwater estuaries, rather than inhabiting exclusively freshwater systems.
The La Plata dolphin is the only species in its genus, and is often placed in its own family, the Pontoporiidae. It was first described by Paul Gervais and Alcide d'Orbigny in 1844 (the species epithet blainvillei commemorates the French zoologist Henri Marie Ducrotay de Blainville). The La Plata dolphin is also widely known as the Franciscana - the Argentine and Uruguayan name that has been adopted internationally. Other common names are the toninha (the Brazilian name) and cachimbo.
The La Plata dolphin has the longest beak (as a proportion of body size) of any cetacean — as much as 15% in older adults. Males grow to 1.6 m (5 ft, 3 in) and females to 1.8 m (5 ft, 10 in). The body is a greyish brown colour, with a lighter underside. The flippers are also very large in comparison with body size and are very broad, but narrow on joining the body, so are almost triangular in shape. The trailing edges are serrated. The crescent-shaped blowhole lies just in front of a crease in the neck, giving the impression that dolphin forever has its head cricked upwards. The dorsal fin has a long base and a rounded tip.
The La Plata dolphin weighs up to 50 kg (110 lb), and lives for up to 20 years. The gestation period is around 10–11 months and juveniles take just a few years to mature. Females may be giving birth by the age of five.
The animal is very inconspicuous—it moves very smoothly and slowly—and can be difficult to spot unless estuary conditions are very calm. It will commonly swim alone or in small groups. Exceptional groups as large as 15 have been seen. La Plata dolphins are bottom feeders and gut inspections have revealed they eat at least 24 different species of fish, depending on which species are most common. They will also take octopus, squid and shrimp. They are, in turn, hunted by killer whales (orcas) and several species of sharks.
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Wikipedia