The Collaborative International Dictionary of English v.0.48:

Tatou \Ta*tou"\ (t[.a]*t[=oo]"), n. [Cf. Tatouay.] (Zool.)
   The giant armadillo (Priodontes gigas) of tropical South
   America. It becomes nearly five feet long including the tail.
   It is noted for its burrowing powers, feeds largely upon dead
   animals, and sometimes invades human graves.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tatou
    n 1: about three feet long exclusive of tail [syn: giant
         armadillo, tatou, tatu, Priodontes giganteus]