C.S. Lewis' The Chronicles of Narnia featured "Talking Animals" alongside normal animals. This was explained in the sixth book, a prequel; the next book had a Talking Animal turn back into a normal animal out of sheer terror. In the fourth book, the main characters accidentally eat part of a Talking Animal; when they learn this fact, they are as disgusted as if learning they'd "just eaten a baby" and stop eating.
They are all different species (gena, whatever) from the dumb animals they resemble and do not interbreed.
They are closer to human-sized than the corresponding dumb animals. A talking mouse is about two feet tall, while a talking bear would be bigger than a human but never as big as a full-grown wild bear.
If they have opposable thumbs or the dumb animal they're related to can pick things up in its paws, they will use tools and sometimes even clothes.
Off of that, Talking Animals are considered citizens. Non-talking ones are just regular animals, and can be used for food and/or labor. In the last book, Tirian and Jewel see a Calormene using a whip on a horse. When they think its a regular horse, they find it mildly distasteful. When they learn its a talking horse, they are both so overcome with rage they promptly murder both of the Calormene.
Put it all together and it would be hard to mistake a talking animal for a dumb animal by accident, and a talking carnivore has more in common with a talking herbivore than with a dumb carnivore.
In some incarnations of L. Frank Baum's Oz series, creatures that talk are collectively "Animals" (and specifically Lions, Geese, etc.) while creatures who do not are "animals" (and conversely lions, geese, et al.).
Toto never speaks in the original "Wonderful Wizard of Oz". When it is established in a later book that all animals in OZ can talk, even if they've arrived from our world (Oz continuity is... complicated), Toto says a few words at Dorothy's coercion; but since she always understands what he means even when he doesn't talk, he doesn't see the point. In another book, he rather cheekily states that although he could always talk, he "never had anything to say to any of you."
Philip JosÚ Farmer has fun playing with this in his revisionist novel, A Barnstormer In Oz. There is an utterly terrifying scene where a talking owl eats a talking mouse that is begging for mercy.
In Gregory Maguire's Wicked and Son of a Witch, set in an alternative Oz, Animals are persecuted by the Wizard's regime and that of his successors, in response to which many of them go into hiding, pretending to be animals, rather than Animals. Now try to get that straight. Like it's source work, it's eventually revealed that animals can be taught to speak and thus become Animals (though in the books, this process has only completely succeeded with one Animal), not that this matters to some Ozians, who kill and eatthem regardless of sapience. Let's not start with the portion in the second book where a Cow describes her newborn children being carted off for veal.
In the later books, Billina (a non-Oz chicken, originally named by a kid with little understanding of gender) become the matriarch of an extensive family of fully sapient and very educated chickens. When auntie Em and her husband move to Oz, Em sees nothing wrong about walking into their private community and try to grab a few for dinner, and even matter-of-factly explains this stance to Billina.
Strangely, the major enemies in the first two books were giant, intelligent insects and the (eventual) allies of the protagonists, the Weavers — giant spiders. "My husband was here for breakfast, and we only just finished", indeed...
And Foster still forgot at least once, having Sorbl the owl eating a mouse sandwich despite reacting the notion with disgust in the previous book.
Played straight with salamanders. They're depicted as non-intelligent beasts of burden in two of the novels, yet a salamander wizard-and-apprentice pair are characters in The Moment Of The Magician. Possibly they, like insects or spiders, have both sentient and non-sentient representatives.
In Chorus Skating, the villain Manzai gets himself killed by this trope. He's unwittingly transported to a world (presumably ours) where bears like himself are non-sentient, and tries to order some grizzlies to catch fish for him. Turns out Bears Are Bad News can apply even if you are one...
The Katurran Odyssey takes place in a world populated entirely by Intellectual Animals. There is some pretty spectacular Carnivore Confusion to be found here, but for the most part everyone else is treated equally... except for in the city of Od Ashud. If you aren't a Golden Monkey, expect to be added to the Empress' zoo.
In Time Waits For No Mouse and its sequels this was averted by making insects the equivalent of animals for the talking rodent main characters. Grasshoppers are apparently their equivalent of cattle.
The sci-fi novel I, Weapon, manages a form of Furry Confusion without actually involving Furries (although some have fur). The series is written in a far future where humans were nearly wiped out by invading aliens with the surviving members having largely speciated into various specialized forms to survive on far planets. One of the groups of humans was bred by the overlords for muscle, lack of brains, and large earlobes (the aliens thought earlobes were fascinating and bred for it as a decorative traits). At the time when the human races begin re-establishing contact, they decide that the kindest thing to do for the meat race is to continue breeding and using them as food. One of the scary aspects of the book is that it's implied that, outside of the huge earlobes, the meat race are the ones who look most like what we think of as humans.
The minotaurs in the Dragonlance universe ride horses (specially bred to carry them, since they're bigger than people). They also keep livestock, though they don't keep cattle, they've instead bred sheep to cattle size as a substitute. They are explicitly aware of this trope. Calling a Minotaur a "cow" is roughly the equivalent of the n-word, as they are very conscious of their resemblance to said animal and don't take kindly to being reminded of it.
In a Russian series of books called Prostokvashino (and the animations based on them), Uncle Fyodor lives with a cat and a dog, who talk and possess intelligence. The cat and the dog recall living with the same professor in the past, who apparently taught them how to talk. There is also an intelligent beaver. They also own a cow, and later a calf, both of whom are normal, non-sentient animals.
Some Richard Scarry books actually have the inhabitants of Busytown (all anthropomorphic animals) coexist with non-anthropomorphic animals. For example, one book actually showed a pig farmer raising non-anthro pigs!
The Polish books about Koziolek Matolek. Matołek the goat, and later his family, seems to be the only anthropomorphic animal around (though all animals are sapient, as usual in children's literature). The humans he meets react variously; some treat him as an ordinary person, some call for the butcher immediately upon spotting him, and then there are those who initially treat him as a human but try to make him into a stew once he displeases them.
A few of the species in the Redwall series flip-flop on their level of sapience. Eels appear to be monsters in Taggerung, but in Mossflower an deal is made with a talking eel to free him in exchange for their lives. In the third book, Basil Stag Hare jokes that the magicians be allowed in Redwall "as long as they don't pull rabbits out of hats", which makes one wonder how that trick would work when there are no humans in the series. Reptiles also vary in terms of intelligence, especially snakes. Amsodeus Poisonteeth from the first book was an intelligent, articulate villain, but later snake characters, like the giant water snake Deepcoiler, have only animalistic intelligence.
In Just Go to Bed, Little Critter pretends to be a rabbit. It could be justified in that he might have been pretending to be another person who just happened to be a rabbit.
In Just Pick Us, Please!, Little Critter and his friends help the local animal shelter to host a pet fair, which includes a hodgepodge of anthropomorphic animals all adopting various pet animals, including on one page an anthropomorphic rabbit holding what very much appears to be a non-anthro rabbit.