The Collaborative International Dictionary of English v.0.48:

Ululate \Ul"u*late\, v. i. [imp. & p. p. Ululated; p. pr. &
   vb. n. Ululating.] [L. ululatus, p. p. of ululare to howl,
   yell, shriek.]
   To howl, as a dog or a wolf; to wail; as, ululating jackals.
   --Sir T. Herbert.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ululate
    v 1: emit long loud cries; "wail in self-pity"; "howl with
         sorrow" [syn: howl, ululate, wail, roar, yawl,
         yaup]