Why Are Amazon River Dolphins Pink?

Amazon river dolphins, also known as botos, are often pink due to a combination of factors, including their diet, environmental conditions, and unique biological characteristics. Their coloration is partly influenced by the murky, sediment-rich waters of the Amazon and Orinoco river basins, which contain minerals that may affect their skin tone. In addition, their diet—consisting of various fish and crustaceans—can contribute to pigmentation changes over time. These environmental and dietary factors, along with the visibility of blood vessels and scar tissue beneath the skin, help explain the distinctive pink hue seen in many of these dolphins.

Another factor contributing to the pink hue of Amazon river dolphins is age and maturity. Young Amazon river dolphins are typically gray, and as they mature, their skin becomes mottled pink and gray, with some adults eventually turning bright pink. This change is usually more pronounced in males, which are often more vividly colored than females.

Social interactions and behavior may also influence the pink coloration of these dolphins. During social interactions, such as play or competition, increased blood flow to the skin can cause the dolphins to appear more pink. This is similar to how humans might blush when excited or physically active. In some cases, the pink coloration may also signal health or vitality and could play a role in mating displays or other social dynamics.