Hobbies And Interests
Eyesight
The eyesight of freshwater dolphins is so poor that they are often called blind dolphins. The eyes of the Ganges River dolphin even lack lenses. Their murky river habitats with poor visibility make eyesight less useful, resulting in devolution. The dolphins are highly vocal and rely on their echolocation abilities to navigate and catch their prey. Their poor eyesight, however, makes them vulnerable to contact with boats and fishnets.
Flippers, Fins and Colors
Freshwater dolphins have stocky bodies, broad flippers and a much-reduced dorsal fin compared to saltwater species. A large dorsal fin would get tangled up in branches and river debris. The Ganges and Indus river dolphins use their long flippers to find food, trailing them in the mud as they swim on one side. Both the Ganges and Indus species are similar in color to the waters they inhabit -- a brownish gray. The Amazon dolphin, or boto, is an amazing shade of pink. Its blood vessels run directly beneath the skin, which is thinner than marine dolphins and making it appear pink. Scientists speculate that the color may help camouflage them in muddy water.
Beaks
All three species of freshwater dolphins have long beaks designed for grabbing fish hiding in tangled branches and rooting around in muddy river bottoms for crustaceans. The Amazon River dolphin has a distinctive bulbous forehead making its beak seem even more elongated. Indus and Ganges river dolphins have long beaks that swell at the tip.
Neck Vertebrae
Specially adapted to move in confined spaces and shallow water, the neck vertebrae of freshwater dolphins are not fused. Unlike marine species, their neck vertebrae permit them to bend at up to 90-degree angles. The ability to slither through small spaces and out of shallow water with increased flexibility is unique to freshwater dolphins.