AMAZON RIVER DOLPHIN
The Amazon River Dolphin, also commonly known as the pink river dolphin as well as boto, are similar to the Amazonian manatee in that they only inhabit freshwater—a constraint only two other dolphin species have. They can be found throughout the Orinoco and Amazon river basins stretching into Brazil, Colombia, Bolivia, Guyana, Peru, Venezuela, and Ecuador. Unlike the manatee, however, these animals have relatively abundant populations despite the threats to communities inhabiting certain environments.
The boto reach up to 2-3 meters, averaging around 6.5 feet, and weigh as much as 300 pounds. This makes them the largest of the freshwater dolphins. The boto come in, not surprisingly, varying shades of pink. They can range from rosy-pink to gray-pink, and some can even be an albino white if their pigmentation is bleached. A long, thin snout stands out against their short, round heads marked by a dominant forehead.
The prominent forehead does not actually house their brain. Rather, the forehead serves as a biological lens to focus their echolocation. With their incredibly small eyes, the dolphins rely on sonar rather than sight—another evolutionary trait that allows them to navigate the Amazon’s murky waters easily. This serves them well as the Amazon Basin continues to grow more polluted.
The dolphin’s unique pink color is impacted by their exposure to the sun. Dolphins who inhabit murkier water have a brighter pink hue and can actually ‘blush’ a more vivid pink when excited.
Boto who inhabit more clear waters tend to have a lighter pigmentation due to the exposure to the sun.
The boto also has the singular ability to turn their head from one side to the other. This is an evolutionary trait that helps them survive in the Amazonian river system. When the river floods, they are able to use the ability to turn their heads as well as their ability to paddle forward with one fin while paddling backward with the other to navigate through trees and other obstacles. Truly, the boto have adapted incredibly well to their environment. They also have free- floating vertebrae that allows them to perform 180 degree turns with ease.