Why are parables and fables allegories?

A fable is a short, pithy animal tale, most often told or written with a moral tagged in the form of a proverb. Thus to convey a moral is the aim of most fables, and the tale is the vehicle by which this is done, providing illustration and compelling argument for the moral. To be specific, the fable does not originate as a folktale, though it may make use of folk material, and can also be composed into a culture and exchanged as traditional oral folklore. There are many fables in the world originated from different country but the oldest fables are either Aesopic in origin or Asian roots. The oldest fables are created dating back several centuries B.C.E.