Woof?

This may sound kind of naive or just plain ditzy, but why the heck do Bears say 'woof' to each other? I mean, I know what it means, and its one of my favourite greetings, but I don't remember Goldilocks being woken up with a 'woof', do you? Curiously though, it seems that even Belles Bears includes a dog 'woof woof' on its range of sounds you can add to your build-your-own-bear project, though EduQnA.com answers 'What noise does a bear make?" with: growl (belly rumberling) roar (spots food) stamp stamp (spys food gives chase) thud thud (steps on food source to kill it) growl (satifised its dead) munch munch (eats) burppppppppp (finishes) pitter patter pitter patter (creeps around for pudding) rumble rumble (stomach settling) .