As part of the Rolex and National Geographic Perpetual Planet Amazon Expedition, National Geographic Explorers Fernando Trujillo and MarÃa Jimena Valderrama are tracking the Amazon’s charismatic river dolphins through several tributaries to understand more about their populations, movement and health. As sentinels of the river, the dolphins provide scientists with clues about what is happening throughout the Amazon’s ecosystems and the rest of the food web. River dolphins are currently facing several threats, including conflict with fisheries, vessel traffic and mercury pollution, so monitoring their changing numbers can provide insight into the success of conservation efforts and where they should be focused. Discover more https://on.rolex.org/3uxtkWD#Rolex#PerpetualPlanet