The Amazon river dolphin is famously known for developing pink coloration.
The Amazon river dolphin, also called the boto, lives in freshwater systems across much of the Amazon and Orinoco basins. Adults can appear pale pink, especially males, although individuals may also be gray or mottled. The pink tone is associated with skin coloration and blood vessels showing through the relatively light skin; scars and age can make the color more pronounced.
Unlike ocean dolphins, botos have flexible necks and broad flippers that help them maneuver among submerged roots, branches, and flooded forest. Their long snouts are useful for searching through sediment and vegetation for fish and other prey.
People sometimes assume every individual is bright pink, but that is not true. Calves are generally darker gray, and coloration varies with age, sex, water conditions, and scarring. The species is also threatened by habitat alteration, fishing activity, and accidental capture.