The exchange student was growling at her.
When Brutus is growling or barking at something, he's warning you.
Both inched toward her, the inhuman growling filling the hall.
When alarmed, they rush to their burrows, and if these are disturbed utter a growling sound.
From the third room came sounds of laughter, the shouting of familiar voices, the growling of a bear, and general commotion.
You saw something in the forest; Brutus was growling and you had to be told to get out of there?
He backed up a few feet and stopped, lowering his head and growling in a way that made the hair on the back of her neck stand on end.
He had nearly finished this last task when a low growling was suddenly heard and the horse began to jump around and kick viciously with his heels.
Brutus started growling at it and Josh said we should go back.