• (n.) A kind of dolphin (Platanista Gangeticus) native of the river Ganges; the Gangetic dolphin. It has a long, slender, somewhat spatulate beak.
Soo'soo noun (Zoology) A kind of dolphin ( Platanista Gangeticus ) native of the river Ganges; the Gangetic dolphin. It has a long, slender, somewhat spatulate beak. [ Written also susu .] 
The soosoo is a cetaceous mammal similar to a dolphin. It is found in the Ganges and grows to about four metres in length.