The Indus Dolphin (Platanista minor) or Bulhan, as it is locally known is a unique river cetacean that only occurs in Pakistan and one of most endangered Cetacean species of the world. Most dolphins and whales are found only in the sea, but the Indus River dolphin survives only in freshwater. Other river dolphin species occur in the Yangtze River in China, the Amazon & Orinoco in South America and the Ganges, Brahmaputra and Meghna River System in India, Bangladesh and Nepal.

The Indus River dolphin is a very unusual kind of cetacean. It is thought to have its origin in the ancient Tethys Sea, which dried up around fifty million years ago forcing the dolphin to adapt to its only remaining habitat - the rivers. Living in the turbid waters of the Indus for millions of years has meant that its sight has been replaced by a sophisticated sonar system known as echolocation, which it uses to steer and hunt underwater. This species represents a unique genome, an irreplaceable part of the biodiversity of life on earth. The Ganges dolphin, a similar relative of the Indus River dolphin, is a distinct species.

Historically the dolphins existed from the Indus estuary up into the foothills of the Himalayas at Attock. They were also found in all major Indus tributaries, including upstream in the River Ravi. Since the construction of the Indus irrigation system, the dolphins have declined dramatically. Now they remain only in a short stretch of the main Indus River in small populations, which have been separated by impassable irrigation weirs or barrages across the Indus River.