here and here.)
In some works of fiction, diverse animal species stand and walk upright, have opposable thumbs, speak, wear clothes, live in houses, drive cars, read newspapers and commute to work. These fictional characters are not cats, dogs or bears but human beings with feline, canine or ursine heads.
In some other works of fiction, wild animals have language and a human level of intelligence while otherwise remaining wild, inhabiting natural, not artificial, environments and continuing to eat grass, worms or whatever is their appropriate diet. These composite creatures are not, in the literal sense of the word, anthropomorphic - or humaniform - animals but they are humanized animals, nevertheless. (Rupert Bear had both a Rabbit family living in a house in the village and a talking rabbit in a rabbit-hole out in the countryside! - which made me question the coherence of the whole scenario.)
(I am going somewhere with this, I think.)
Poul Anderson asked what might succeed mammals, John W Campbell answered the question and Anderson adapted Campbell's answer as the flying, intelligent Ythrians. More generally, could there be intelligent beings whose bodies were completely at home in wind, rain, storm and sea without needing clothes or buildings? They would need to have some level of technology and limbs for manipulation as well as locomotion. They might have bypassed or superseded urban civilization? Such beings might synthesize the best features of animality and rationality.
Ludwig Wittgenstein, CS Lewis and Poul Anderson addressed the issue of intelligence in animals. It is appropriate to cite a philosopher as well as two writers of fiction because they address the same questions differently. Philosophers abstract; poets and novelists concretize; playwrights dramatize. What is life? To be or not to be? Philosophy and Literature would make a good combined University degree course. To share a philosophical tradition is to share an approach to basic questions, not to agree on answers. A University friend and I remained analytic philosophers when he studied theology and became a Presbyterian minister. (Alan, if you are reading, please comment.) The Christian Lewis and the agnostic Anderson both used fiction to address the relationship between animality and rationality but let's start with the philosopher, Wittgenstein, after I have had a coffee break.