The Collaborative International Dictionary of English v.0.48:

Scut \Scut\, n. [Cf. Icel. skott a fox's tail. [root] 159.]
   [Obs.]
   The tail of a hare, or of a deer, or other animal whose tail
   is short, esp. when carried erect; hence, sometimes, the
   animal itself. "He ran like a scut." --Skelton.
   [1913 Webster]

         How the Indian hare came to have a long tail, whereas
         that part in others attains no higher than a scut.
                                                  --Sir T.
                                                  Browne.
   [1913 Webster]

         My doe with the black scut.              --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scut
    n 1: a short erect tail