Amazon River Dolphin
This is a freshwater species, known locally by its Portuguese name boutu vermelho, which translates as "red dolphin" and describes its distinctive colouration.
Amazon river dolphin's ancestors entered the Amazon from the sea, and adapted to living in freshwater surroundings. Their neck vertebrae are not fused, so they can move their heads through 90 degrees from side to side, using this flexibility to search for prey, aided by echolocation. Another unique feature is the sensory hairs on the beak, which detect edible items in muddy water. These river dolphins also have good vision and hearing, though, and are very agile by nature.
Amazon river dolphins live in the wide rivers of the Amazon Basin. In the rainy season, they move into flooded areas of forest and up swollen streams into lakes. They may become isolated in pools when waters recede, but most are able to survive by eating the river fish that are trapped with them.
Amazon river dolphins live in small groups. They are thought to defend the areas around them and will stay in an area as long as there is enough food. They breathe at least once a minute, through the nostrils on the top of their head. They dive down to the bottom of rivers to search for food, using their bristled snout to root through mud and weeds.
When young, Amazon river dolphins have metallic blue and grey upper bodies with silvery bellies. As they age, the dolphins' upper bodies gradually turn pinkish. Their long snouts are covered with sensitive bristles.
Like other dolphins, Amazon river dolphins may use echolocation to find their way in the murky river waters. They sometimes feed in the same areas as giant otters. It may be that the hunting behaviour of otters drives fish out of the shallows towards the dolphins.
Distribution: Widely distributed throughout the Amazon river basin in northern and central South America, occurring both in rivers and lakes.
Habitat: Dark, slow-moving river water.
Weight: 85 - 160 kg (187 - 350 lb); males are slightly bigger.
Length: 1.8 - 2. 7m (6 - 9 ft); the largest of the 5 species of river dolphin.
Maturity: 5 - 7 years.
Gestation Period: Up to 365 days.
Breeding: 1; weaning probably occurs within a year.
Food: Mainly piscivorous, hunting large catfish and piranhas; also feeds on crabs.
Lifespan: Up to 30 years.
Young Amazon river dolphins become increasingly pinkish in colour as they mature.
There is a hump rather than a dorsal fin on the back, which may break the surface of the water.
These are very large, helping the dolphin manoeuvre easily in shallow or thickly vegetated water.
The beak is long, with sharp teeth at the front and molar teeth behind.
A FORESTED WORLD
Some areas of the forest flood seasonally, and then these dolphins will expand their range temporarily, in pursuit of prey.