growl·ing /ˈgraʊlɪŋ/
  Growl v. i. [imp. & p. p. Growled p. pr. & vb. n. Growling.]  To utter a deep guttural sound, as an angry dog; to give forth an angry, grumbling sound.
  growling
       n 1: a gruff or angry utterance (suggestive of the growling of an
            animal)
       2: the sound of growling (as made by animals) [syn: growl]