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La Plata Dolphins

















What is taxonomy?

It should be noted that there is debate in the scientific community about how many river-dolphin taxonomic families should exist. The debate about whether all genera of river-dolphins represent four evolutionary departures from primitive dolphins and whether each deserves separate familial taxonomic status continues today. In the past, many authors grouped river-dolphins into one taxonomic family while others grouped them into three families. This issue is still unresolved.

La Plata dolphins are also called the franciscana river-dolphin.  They are extremely shy and evasive by nature. Human knowledge of them is surrounded by superstition as there are so few facts known about them.  The La Plata dolphin and other river-dolphins are, in general, smaller and less well-known than most other dolphins

Interesting Facts:

  • La Plata dolphins have the longest beak-to-body ratio of any dolphin.
  • La Plata dolphins are limited in their distribution to temperate and coastal waters of eastern South America.
  • La Plata dolphins are known to fishermen as "the white ghost" because their bodies are light in color and because they flit away when they see humans. 
  • The La Plata dolphin and other river-dolphins are considered rather primitive by comparison to other cetaceans with their long beaks, interlocking conical teeth, and their poor eyesight


What should I know about La Plata dolphins?

Where do La Plata dolphins live?

La Plata dolphins are exclusively marine however they "earned" the title of river-dolphin because they inhabit the salt-water estuary of the La Plata River.   They inhabit shallow waters in South America from the coast of the Atlantic Ocean to the Valdes Peninsula and from the La Plata River delta of Argentina to the Tropic of Capricorn near Rio de Janeiro of Brazil.  A sighting of a La Plata is very special because these dolphins reside in isolated areas and are rarely seen by humans.

How many La Plata dolphins are there?

The La Plata dolphin population is unknown.

How can I identify a La Plata dolphin?

La Plata dolphins are considered extremely primitive marine mammals.  They have disproportionately small heads, pronounced melons, short bodies, and long slender beaks.  They are light colored, either mostly white or pale brown on top converging into lighter brown on their bellies.  La Plata females are slightly larger (5.5 feet or 1.7 meters) than the males (5 feet or 1.5 meters).  All La Plata dolphins have 50 or more sharp teeth and are highly adapted to their fresh water environment with their large beaks and spatulate flippers. 

How well can a La Plata dolphin  see or hear?

La Plata dolphins have very poor vision. Not much is known about their hearing.  La Plata dolphins also have very sensitive echolocation which allows them to navigate in turbulent and murky river waters.   

What do La Plata dolphins dolphins eat?

La Plata dolphins are primarily bottom feeders and consume a wide variety of fish, as well as shrimp, squid, and octopus.

How do La Plata dolphins have babies?

La Plata dolphins are capable of reproducing when males are 4.5 feet (1.37 meters) long and females are 4.6 feet (1.4 meters) long.  La Plata dolphin calves are born 2.7 feet (0.8 meters) long after a 12.5 month gestation period, usually from October to January. La Platas nurse for nine months and tend to give birth every two years. 

How long do La Plata dolphins? How do they die?

La Plata dolphins are thought to live about 20 years.  La Plata dolphins were often killed accidentally in nearshore shark gillnets through the late 1960s.  This mortality decreased markedly as the shark fishery moved progressively offshore.

Where can I find more information about La Plata dolphins?

Books and the world wide web are excellent places to learn more about marine mammals. 


  • Leatherwood, Stephen. Reeves, Randall R. Foster, Larry.   The Sierra Handbook of Whales and Dolphins.  Sierra Club, San Francisco, CA.  1983.
  • Leatherwood, Stephen.  Reeves, Randall R. Perrin, William F.   Evans, William E.  Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic waters; A Guide to their Identification.  Dover Publications, Inc., New York, NY.  1988.
  • Wynne, Kate. Folkens, Pieter. Guide to Marine Mammals of Alaska.  Alaska Sea Grant Program.  University of Alaska Fairbanks, Fairbanks, AK.  1992. 

World Wide Web

There are many more sources to learn about cetaceans.   Check with MML's online library or your local librarian for her or his recommendations.

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This portion of the MML website is intended for a student audience and their educators.
Information within the education website should not be cited in scientific journals or publications.

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