The world of Felidae presents us with cats that seem only mildly anthropomorphized, in a phsychological way rather than physiologically. They are more or less as intelligent as average humans, self aware and aware of the human world and its customs, speak to each other, read and -- albeit only in the rather exceptional case of Pascal -- can learn to use a computer. But in their physiology (except for a little artistic freedom of the animation) and behaviours they still seem to be bound to their existence as cats, they look like cats, walk like cats, eat like cats, fight like cats, and f--k like cats. Add to this that other animals like rats and crows don't seem to be anthropomorphized at all. So while the increased intelligence and the reading ability might be unusual, this doesn't so far seem to interfere with our observed reality that much, only enhance it with a "look behind the scenes" of the cats' world which might as well be understood as largely metaphorical.
But there is one significant moment where this interpretation gets shattered from the ground and an actual deviation from our reality is indeed suggested, but there isn't made much more out of this in the further course of the story. During Francis' examination of Dr. Preterius' video journal the doctor at one point raves that Claudandus has started to speak to him:
Yes Claudandus, talk to me, he he, fascinating idea. The animal has no sense of humour. What did he say, that I should release him from his cage, and face him, in hand to hand combat? What's this, I've got to save Claudandus?
Though, at this point the good doctor is already on his best way to insanity, not to speak of his drinking problems, so it might as well be a hallucination. Yet, when Francis later confronts Pascal (now revealed to be Claudandus) he says that he indeed spoke with Preterius, much to Francis' surprise:
Pascal: Yes, I'm Claudandus, you're right. I was in the laboratory and I did survive Preterius' unspeakable tortures. And when he eventually went mad I spoke to him!
Francis: You spoke to a man?!
Pascal: He was fascinated, he let me out of my cage.
But this isn't touched upon further and I'm not sure what to make out of this and what it's actual implications for the depicted reality are. Does that actually present a deviation from our observed reality? Does that mean the cats are generally able to speak to humans but refrain from doing so? Or is Pascal a special case (maybe in relation to the experiments Preterius conducted and him being the only one on which his tissue glue worked)? Or was this only facilitated by Preterius' advanced insanity? Or does Pascal himself overinterpret the events and it was really only a hallucination by Preterius? Or is this an utter surprise and mysterious event in the cat world, too? I see that this might not be entirely answerable by the movie alone and it might be that only the novel can present any further insights here, if the movie was true to it in this regard at all. Or was this not elaborated further anywhere?