The Collaborative International Dictionary of English v.0.48:

Suslik \Sus"lik\, n. [Russ. s['u]slik'.] (Zool.)
   A ground squirrel (Spermophilus citillus) of Europe and
   Asia. It has large cheek pouches. [Written also souslik.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

suslik
    n 1: rather large central Eurasian ground squirrel [syn:
         suslik, souslik, Citellus citellus]