River dolphin is a type of dolphin that lives in fresh or slightly salty water. River dolphins inhabit warm rivers and lakes of Asia and South America.
Both river dolphins and marine dolphins belong to a group of mammals called cetaceans. But these two types of dolphins differ in appearance. For example, the snout of a river dolphin measures about 1 foot (30 centimeters) long, approximately four times as long as that of most marine dolphins. River dolphins have smaller eyes than marine dolphins, and their vision is poorly developed because they live in dark, muddy water. This environment also makes river dolphins less active than marine dolphins. River dolphins feed primarily on fish.
The largest river dolphins usually grow up to 8 feet (2.4 meters) long, but most are smaller. River dolphins may be white, pink, yellow, brown, gray, or black in color.
There are at least four living species (kinds) of river dolphins. The Amazon River dolphin, also called the boto or pink dolphin, lives in rivers of northern South America. The nearly blind Ganges dolphin and Indus River dolphin inhabit rivers of northern India and Pakistan. The La Plata dolphin, also known as Franciscana, lives in rivers and coastal waters of eastern South America. The baiji, also called the Yangtze River dolphin, historically was found in Dongting Lake in China. However, scientists think the species likely went extinct in the first decade of the 2000’s. All species of river dolphins are threatened by human activities that kill the animals or destroy their habitat.
