Pink River Dolphin (Inia geoffrensis)
(aka Amazon River Dolphin, Boto, Bouto)
Pink River Dolphin, Anavilhanas, Amazonas, Brazil, July 2001 - click for larger image Anavilhanas, Amazonas, Brazil
July 2001

The Pink River Dolphin is one of five species of river dolphins worldwide that live in mainly muddy river systems.

Pink River Dolphin, Anavilhanas, Amazonas, Brazil, July 2001 - click for larger image Dolphins are toothed whales with large brains, acrobatic ability and complex social behaviour. Most have excellent vision but the river dolphins have poor sight. By contrast they have developed sophisticated echolocation which is much more useful as they pursue their mainly fish prey in the muddy river waters.
The habitat in which we saw these dolphins was slightly different in that the Anavilhanas are situated in the clear waters of the Rio Negro. It is found throughout the Amazon and Orinoco river systems below major waterfalls except in the case of the upper Rio Madeira in Bolivia where there is an isolated population which may be a seperate species.

The Pink River Dolphin grows to almost 3 metres in length with males being much larger than females. The head has a long, thin beak and a large bulbous forehead which houses the echolocation organs and can change shape if required.

The dorsal fin is fairly inconspicuous compared to other dolphins. Colouring is variable with younger dolphins tending to be grey and pink becoming more noticeable in older animals. This is because, as the dolphin grows older, its skin becomes more translucent allowing the blood to show through.

Pink River Dolphins are classified as Vulnerable by CITES. The threats come mainly from commercial fishing, poison and hunting for body parts. However, they are rarely hunted by the locals who believe that harming one will cause their babies to develop spina bifida where the skull fails to close and resembles a dolphin's blow hole.

There are illustrations in Eisenberg & Redford, Plate 14; and in Emmons, Page 171.

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