Explanation:

Indus river dolphins are one of only four river dolphin species and subspecies in the world that spend all of their lives in freshwater. They are believed to have originated in the ancient Tethys Sea. When the sea dried up approximately 50 million years ago, the dolphins were forced to adapt to its only remaining habitat—rivers. umbers declined dramatically after the construction of an irrigation system. Most dolphins are confined to a 750 mile stretch of the river and divided into isolated populations by six barrages. They have adapted to life in the muddy river and are functionally blind. They rely on echolocation to navigate, communicate and hunt prey including prawns, catfish and carp.Found only in India and Pakistan, the Indus dolphins are confined to only a 185 km stretch between Talwara and Harike Barrage in India’s Beas river in Punjab.They come in IUCN endangered category.