7.Amazon River Dolphin

This dolphin cannot be found at sea; it is one of the world's few remaining freshwater dolphins. It is found in rivers and lakes in South America, especially the Amazon River. These dolphins are large creatures, weighing up to 350 pounds (160 kg) and measuring up to nine feet (2.7 m) long; however, they lack the usual dorsal fin associated with dolphins. Unfortunately, because dolphins consume the fish that river fisherman wish to catch for a living, they are frequently intentionally murdered. They are also the origin of several myths. Local mythology holds that dolphins are quiet, reclusive, and blind, yet scientists have shown that they are sociable—even aggressive—and have perfect vision. The dolphins range from gray to the pink tint for which they are famous, and scientists have discovered that the pink color develops as the animals mature, with male dolphins having the most rosy coloration. One leading assumption is that the pink on their skin represents scar tissue from the many battles that adult dolphins have. Some believe the pink pigmentation developed to blend in with the red sand in South American riverbeds, allowing them to avoid larger predators.