Incidentally, 'bellow' (with the stress on the first syllable) is what an angry bull does. Below (with a single l, and stressed on the second syllable) is what you want.
Not always a bull, and bulls don't always bellow. More often they snort. But if an animal bellows, it has to be quite big. A grown man can bellow if he's very angry, but you'd never hear a child bellow.