The Collaborative International Dictionary of English v.0.48:

Taguan \Tag"u*an\, n. [From the native name in the East Indies.]
   (Zool.)
   A large flying squirrel (Pteromys petuarista). Its body
   becomes two feet long, with a large bushy tail nearly as
   long.
   [1913 Webster]
   [1913 Webster]

WordNet (r) 3.0 (2006):

taguan
    n 1: East Indian flying squirrel [syn: taguan, flying
         marmot, flying cat, Petaurista petaurista]