tor.com recently posted this article on Why Anthropomorphic Animals Will Always Have a Place in Fantasy
It starts out with the earliest surviving tale
One of the earliest examples of authors turning to animals to tell human stories comes from Works and Days, a poem by the ancient Greek Hesiod that doubles as an early farmer’s almanac. Lamenting that mankind has fallen far from the gods’ first and most successful attempt to build a race of mortals, Hesiod uses a fable to illustrate the brutality of the “age of iron.” A hawk grasps a nightingale to carry it off to eat, and mid-flight, scolds the smaller bird for crying out in pain:
Goodness, why are you screaming? You are in the power of one much superior, and you will go whichever way I take you, singer though you are. I will make you my dinner if I like, or let you go. He is a fool who seeks to compete against the stronger: he both loses the struggle and suffers injury on top of insult. (Lines 207-212, M.L. West translation)
Although it goes into the telling of several more of these tales. It all comes down to what most of us already know that anthropomorphic animals are used as an analog of humans without all the preconceived notions.