Friday, July 15, 2011

Interesting Animals: Amazon River Dolphin

The amazon river dolphin (Inia geoffrensis)

The Amazon river dolphin is also known as the boto, bufeo, bouto. Of all of the cetaceans (whales), these are some of the most unique. They are the largest of the freshwater dolphins, reaching up to nine feet (2.7 m) in length. Gray as juveniles, they fade with age to become distinctly pink in color and then white. The pink can be surprisingly bright. These dolphins have a very distinctive head with a prominent domed forehead, long beak, and small eyes. Despite this, they have good vision and also a good sense of hearing. They feed on fish and crustaceans and are quite curious in nature. Hairs found on the beak are thought to aide the dolphins when sifting through mud for food.
Boto showing their curiousity

The boto is found throughout north and central South America and may possibly be several distinct subspecies as populations can vary in appearance (as seen in the two images I've used). Natives have a taboo against killing these animals, but other cultures that have come to the area have no such qualms. Because of this, the numbers of these unique dolphins have fallen from what they once were. The IUCN red list currently lists them as Data Deficient but they have previously been listed as Vulnerable. Hopefully, the populations are doing well.

Images are from Wikimedia Commons under creative commons licenses: one, two


  1. Do you know if the Chinese River Dolphins have been declared extinct or not?

  2. From what I can find, yes. There was a survey done in 2006 that came back with no dolphins spotted at all. Even if they managed to miss a few, there is really no luck for the population to recover. A population is considered "functionally extinct" at this point.

    Here's some links about their status. All confirm it:

    National Geographic
    IUCN Red List