The Ganges river dolphin (Platanista gangetica) is a species of freshwater dolphin classified in the family Platanistidae. It lives in the Ganges and related rivers of South Asia, namely in the countries of India, Nepal, and Bangladesh. It is related to the much smaller Indus river dolphin which lives in the rivers of the Indus Basin in Pakistan and northwestern India.
It is also known by the name susu (popular name) also shihu (Assamese: শিহু) in Assam shushuk (Bengali: শুশুক) in West Bengal and Bangladesh and Uttum (Chittagonian: উত্তুম) in Chittagong region. The Ganges river dolphin has been recognized by the Government of India as its National Aquatic Animal and is the official animal of the Indian city of Guwahati. Its first occurrence, within the Hooghly River, was documented by William Roxburgh.