Pink dolphins are a rare species of river dolphin found in the Amazon and Orinoco rivers in South America. Unlike other dolphin species, they live exclusively in freshwater rivers. Pink dolphins have 40% larger brains than humans and their skin color ranges from pink to gray depending on age and emotional state, with their skin becoming brighter when excited or embarrassed. They can grow up to 10 feet long and weigh over 300 pounds, making them one of the largest freshwater aquatic mammals.