Platanistidae – Asian river dolphin

The Asian river dolphins, specifically the Ganges river dolphin (Platanista gangetica gangetica) and the Indus river dolphin (Platanista gangetica minor), present a poignant example of adaptation and survival in the freshwater ecosystems of South Asia. These remarkable cetaceans, residing in the sprawling river systems of the Ganges and Indus, are endowed with extraordinary adaptations that allow them to thrive in environments far removed from the open seas typically associated with dolphin species.

One of the most fascinating aspects of these dolphins is their near blindness. The murky, sediment-laden waters of their river habitats render vision almost useless. As a result, they have evolved to rely heavily on echolocation, a sophisticated biological sonar system. By emitting a series of high-frequency clicks and listening to the echoes that bounce back from objects, prey, and other dolphins, they navigate, forage, and communicate in their dark underwater world with remarkable precision.

The swimming behavior of the Asian river dolphins is equally distinctive. Unlike most dolphin species that swim upright, these dolphins often swim on their sides. This unique posture is thought to be an adaptation for foraging in the shallow, uneven riverbeds, allowing them to use one of their flippers to stir the substrate and uncover hidden prey like small fish and crustaceans. Their long, slender snouts are perfectly adapted to snap up such prey, demonstrating a specialized feeding strategy honed by the challenges of their environment.

Moreover, the flexibility of their necks is an unusual trait among cetaceans, who typically have fused neck vertebrae. This anatomical feature enables the Asian river dolphins to maneuver deftly through the complex underwater landscapes of their riverine habitats, navigating narrow tributaries, avoiding obstacles, and pursuing prey with agility.