The Collaborative International Dictionary of English v.0.48:

Soosoo \Soo"soo\, n. (Zool.)
   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.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Susu \Su"su\, n. (Zool.)
   See Soosoo.
   [1913 Webster]