Older Than Radio: Lewis Carroll had a couple scenes like this in Through the Looking-Glass. In the poem "The Walrus and the Carpenter", which is told by Tweedledum and Tweedledee, the two protagonists lure a group of oysters out of their oyster bed for a pleasant chat and walk, only to eat them later. Even worse, while the Walrus seems to be sympathetic towards them in the poem, the Tweedle brothers later tell Alice he was lying, only acting like he was to get more oysters than the Carpenter. Later, Alice herself shows this at the banquet scene after being promoted to Queen, being only too willing to eat the living mutton leg and pudding. (Of course, she had been given a carving knife by the other Queens, who later told her that it would be rude to "cut" someone you had been introduced to. But then, it's hard to make much sense of any of the stuff here.)
Paradise Lost goes with the old idea that all creatures were herbivores before the Fall. When Adam and Eve see the animals of Eden start to attack each other, it's a sign that they really messed up—since the world was specifically created for humans, their sin has completely messed up how nature was supposed to work.
Richard Scarry's Busytown is a bright modern town populated by anthropomorphic animals. The problem of who eats whom is ignored. In fact one can find a family of jolly pigs at the supermarket checking out the butcher's selection. Yes, they are selling bacon, pork and ham.
Turned on its head and parodied with the Let's Meet the Meat scene in The Restaurant at the End of the Universe. The cruelty, Galactic culture decides, is not in eating animals. The cruelty comes in eating animals who probably do not want to be eaten. So they breed livestock that is intelligent enough to know what's going on — and is also disturbingly eager to be devoured. The animal even goes so far as to recommend cuts of itself to the diners.
Arthur is completely squicked out by this concept ("That's not the point! Maybe it is the point, I don't care. I don't want to think about it"), but has come to terms with it by Mostly Harmless, where he meets a whole herd of these creatures, and is quite happy to discuss barbecue arrangements with them. This time it's Random who's squicked.
Dinotopia, which takes place in a land where only about ten percent of the population is human and the rest are Intellectual Animals of all imaginable species, has a relatively clever approach to this problem. All carnivores have switched to a diet of fish and it's implied that those who can (most notably humans) have gone entirely over to veganism. The twist is that some animals refused to make the change and have exiled themselves to the Rainy Basin and Backwood Flats, where they live as their wild ancestors did (similar to The Wild in Kevin and Kell). Interestingly, this is treated by the major characters as more of an alternate lifestyle choice than a break of the rules and such characters are not vilified as one would expect. (At least, not in the book. The movie is another story...)
In one of the not-quite-Canon spin-off novels, a city-dwelling herbivore was shown journeying through the Rainy Basin as she was about to die, providing the carnivores with food. This act was referred to in almost religious terms.
Though the spin-off novel is not-quite-Canon, the act is canon and mentioned in the original book.
To be sure, the assurance that fish are kosher becomes a bit troubling when it becomes increasingly clear in Journey to Chandara that any species with more brains than a sponge can communicate with each-other...
Additionally, leathers, skins, and furs were seen in use by the Dinotopians. Readers had to wait until Journey to Chandara for the explanation: Arthur Dennison is given a new journal bound in the skin of an Intellectual Animal "whose dying wish was to donate his body to science". Um...
Gets even Squickier when you realize that, until the 1800s or so, books bound in human skin were not entirely unheard of...
However, the books suffer a Continuity Drift when in one book the intelligent owl eats mice but every other book in the series has them as intelligent. Either that or the owl didn't care that he was eating an intelligent creature.
Worse, the EXACT SAME OWL reacted with violent disgust when mice were suggested to him as a meal in the immediately previous book.
And one book features humans from our world eating a talking parrot. They didn't know better.
Not particularly avoided in Rudyard Kipling's The Jungle Book due to perspective, as most of the major characters are carnivores. Any distaste animals have for each other has more to do with not following the Laws of the Jungle. There is a scene set during a "water truce" in which Bagheera the panther wishes he could eat branches. A young fawn pipes up that the deer would also very much like it if Bagheera could eat plants, and Bagheera is so amused by this that he agrees not to hunt the fawn once the truce is over. The scene was adapted in Adventures of Mowgli... and the fawn is very cute.
Arguably the animals in The Jungle Book are an imitation of societal classes, with each species following the rules specific to their station because "It's in the blood". Thus predators eat meat and herbivores eat plants, just like gentry fight and rule, and peasants work and pay taxes.
The Disney film pointedly avoids the issue, even though most of the main characters are carnivores. There is a scene in which the tiger Shere Khan is hunting a deer, but fails to catch it.
Bagheera doesn't shy from eating river-turtles though, who would only occur within the river. Also, said turtles are repltiles, but then so are snakes, so where is the line drawn?
On the Discworld some animals have human-like intelligence, due to magical effects, but it's very rare. In Moving Pictures, the cat half of the Tom and Jerry parody has sworn off mice since "Jerry" started talking, and in The Amazing Maurice And His Educated Rodents, the titular cat always offers his prey a chance to speak before eating it. Although when he was a normal cat, he ate a talking rat because he didn't know better. That's how he gained the ability in the first place.
The animals in Moving Pictures were only able to talk because of the influence of Holy Wood. When it's sealed at the end, and they lose their human-level intelligence the cat goes right back to chasing the mouse. Gaspode regains human-level intelligence in an unrelated incident between books.
What's very rare for animals to be able to speak. Werewolves and talking dogs can both talk to normal dogs, who have been shown to be intelligent. When someone mentioned to Death something about humans being more important than chickens, he responded that that's a distinction commonly made by humans. Also, dogs aren't treated particularly well. For example, in Making Money, a dog became the chairman of the bank, but the employees just did what his owner said, rather than using an actual translator.
Because everyone knows dogs can't talk. And also, as established in The Truth, they are still dogs (with exceptions for special cases) and can't really think outside the kennel.
How "intelligent" ordinary dogs are is very up for debate: "Good boy Laddie!"
There has been considerable variation over the course of the series. Gaspode is always quite clever. Other dogs range from Laddie (pretty dumb, but very obedient) to, say, Big Fido (fairly bright when not being Axe-Crazy).
It's also sort of implied that everyone resorts to the "legal fiction" that the owner in question is acting according to the wishes of the dog - in other words, the owner effectively IS the translator. Everyone knows this is a lie, but everyone also ACTS like it's the truth, because admitting the truth would be in bad taste.
Mr Slant says to Those Two Bad Guys in The Truth that via the Watch werewolf, a canine witness would be acceptable in a court of law. Though it's clear that legal precedent isn't the same thing as "sane" in this setting.
The street dogs in Men at Arms seem considerably more sentient than pet dogs like Laddie or Mr. Fusspot. Justified by the intensity of natural selection on the streets of Ankh-Morpork, where a stupid dog quickly becomes an even stupider fur muff and/or takeaway stir-fry. Also, feral dogs probably scavenge off the same refuse that made the rats from Amazing Maurice into intelligent creatures, albeit not often enough for most of them to learn to speak Human.
In the kids' book Tiddler, all the characters are sea creatures. Tiddler, a fish, asks a shrimp for directions at one point. Meanwhile back at Tiddler's school, the other fish kids are eating seaweed and shrimps for lunch.
Redwall is confusing on this issue. The heroes are mostly mice and other herbivores and for the most part the villains are mouse predators. The confusion sets in when it turns out that some predators are also found among the heroes. In one book, the mice fight an army of ravens by teaming up with an owl and a hawk.
The series is inconsistent on vermin's eating habits: in the first book, villainous rat Cluny regards two young rabbits with hunger, and later his horde seem eager to devour a family of dormice. In Salamandastron a band of fox bandits hanker for "roasted dormouse — ages since I tasted that." However, in most other books vermin seem horrified when the concept of eating other mammals is suggested. In Rakkety Tam, a horde of vermin make a habit of eating their enemies, and this is described as cannibalism and seen as particularly monstrous, indicating that this isn't normal vermin behaviour. The first book also has the cat Julian Gingivere express disgust at eating mice, and it's implied to be an odd idiosyncrasy. Yet when we see his wildcat ancestors in the second book, they don't eat mice either, despite being mostly evil.
The good guys never eat birds or eggs, but most vermin do – though it is not generally portrayed as being as horrific as eating mammals. Small birds (larger birds are nearly always shown as intelligent) seem to vary between being shown as similar to fish and as intelligent characters.
Folgrim the otternote Despite being entirely carnivorous in real life, and close relatives of weasels, which are vermin, otters (and badgers) are good guys. in The Legend of Luke, having been tortured by vermin, has a habit of hunting and eating rats; we see him kill one by tearing out its throat. However this is probably less Carnivore Confusion than just that Folgrim is Ax-Crazy.
In John Dies at the End, the two main characters are able to see ghosts. While explaining the source of this ability and its ramifications to a client and prospective love interest, John mentions a hamburger that mooed when he ate it. His business partner and longtime friend, David, silently recalls how it didn't moo, but scream:
Deadhead from the Wild Cards novels channels the memories of any creature whose flesh he eats. When fed a hamburger, he started to moo...
Subverted in the children's book-turned-anime Stormy Night (Arashi no Yoru ni). The story features an unlikely friendship between a wolf and a mountain goat, and the wolf being a carnivore is actually one of the main points of the story. (He is always fighting down the urge to eat the goat, while the goat is painfully aware of this). In the anime the wolf gives up goat meat, but keeps on preying on (sapient) animals such as mice; the goat is not happy about this, but accepts it as inevitable, knowing full well that his best friend would starve to death if he stopped eating meat entirely. In the book they die together.
The Mouse and His Child actually inverts this: the windup mice are caught by a hawk, who mistakes them for real mice, and this leads to the following surreal exchange:
Child: Mr. Hawk, where are you taking us?
Child: What's "lunch?"
(The Hawk bites Father Mouse, realizes they're just cloth and metal, and drops them.)
Hawk: You're not part of the balance of nature! (flies off)
The Katurran Odyssey by Terryl Whitlatch is a wonderfully illustrated, underrated, and highly recommended illustrated novel that has but one flaw. It is really confusing about this issue. It doesn't even stick consistently with what generally appears to be an attempt at the usual "Carnivores Are Mean" (only herbivores can talk) with a "What Measure Is a Non-Cute?" chaser (well, some carnivores can talk - if they are cute) approach. Birds can't talk or act human-like at all...except when they can. Similarly, none of the carnivorous mammals talk or act any differently than their real-world equivalents...except when they do. In the very, very beginning, there's talk of "Pred-folk" and "Prey-folk", indicating that all animals can talk, but this is dumped almost as soon as our hero leaves the big city. There is also a Fossah worshipped as a god by the Lemur tribe and a mention of an ancient menagerie of fierce monsters. Plus, the Golden Monkey kingdom seems to be built on Furry Confusion.
The Chronicles of Narnia first mentions this in Prince Caspian, when the heroes kill and eat a bear but mention they were worried about the possibility it may have been a talking bear (it wasn't). Fortunately, since Aslan thinks of everything, Narnia has dumb animals as well as talking animals, and the latter consider the former to be more different from themselves than humans are from dwarves.
It becomes a plot point in The Silver Chair, where the heroes suddenly become repulsed when they learn that the venison that the seemingly friendly giants have served them was once a talking deer who begged for mercy. There are interesting distinctions raised during the scene: Jill, who's never been to Narnia's world before and hasn't really absorbed the idea, just feels sorrier than normal for the stag and thinks the giants are "rotten" for killing it; Eustace, who has a little more experience with talking animals, including as close friends, is "horrified" in the way "you would feel about a murder"; but Puddleglum, who's native to Narnia, considers himself to have been made a cannibal and takes it as a curse from Aslan for messing up their mission so badly; he almost seems to think that there's no way to atone for what they've done, even though it was accidental, without ending their lives.
The Talking Animals in Narnia don't always stick to their mute relatives' ecological niches, as when Mr. & Mrs. Beaver share a trout dinner with the Pevensies, rather than dining on leaves and bark. And adults (at least, the males) of every species enjoy beer and wine.
Aslan mentions having eaten people in The Silver Chair. Whether or not he meant it literally isn't known — though he did kill the White Witch, so it's not that far-fetched. Since Aslan explicitly is Jesus in Panthera Awesome form (and emphatically not a tame lion), the rules are different for him. It could also be a metaphor for Jesus "swallowing" converts by absorbing them into the faith and eventually into Heaven. This interpretation is reinforced when Aslan mentions having devoured entire "cities and realms," which is exactly what happened in places like The Roman Empire.
Watership Down takes the "fact of life" approach without flinching: all animals can communicate (although not all that well in some cases), but predators nevertheless hunt and kill prey. They aren't portrayed sympathetically, but that's not because they're inherently evil - it's just because the heroes of the book are rabbits.
Interestingly, dogs are portrayed in a far more negative light than cats. Aside from a character in a folktale - who is a drooling idiot compendium of every distasteful canine trait going - they are vicious monsters who don't talk. The cat is a right bitch, but at least she gets to speak her mind intelligently.
This is a major issue in the Brazilian "Just So" Story "The Deer and the Jaguar Share a House". Not only does the jaguar commit the dreadful faux pas of bringing home a dead deer for dinner, but the deer hunts and kills another jaguar (with the help of an anteater).
In the The Obernewtyn Chronicles most of the humans who are aware that animals are sapient (they can only communicate telepathically) become vegetarian. The animals, however, seem to accept the predator-prey relationship as perfectly natural.
The protagonist in The Beasts of Barakhai runs into this problem when the first thing he does when he's sucked into an alternate universe is kill and eat a rabbit. To his horror he learns that all the denizens of Barakhai involuntarily spend 12 hours a day shapeshifted as sentient but mute animals, and he just ate a "sweet old woman". Cannibalism when in beast form was a symptom of insanity and the highest crime in the land.
Tad Williams' novel Tailchaser's Song stars cats and matter-of-factly has them eating smaller mammals that can also talk without portraying them as villains. He still gives into Cats Are Mean a little bit, though: the one time when a cat is about to eat a squirrel, the hero-cat saves it and reunites it with its squirrel lover. Through this act he forges a temporary truce between squirrels and cats, which he realizes is unnatural and unsustainable. In the end, the cats designate a section of the forest where the squirrels will not be hunted, but warn them that everywhere else they'd "better watch their tails."
The Cowardly Lion, the Hungry Tiger, and others in the Land of Oz series tend to be examples of "the carnivore can go vegetarian if he really wants to". Granted, living in a magical land probably alters certain biological rules that would apply in our world. The Hungry Tiger, as explained in Ozma of Oz, is hungry all the time because his conscience won't let him eat all the delicious people and animals that surround him.
In Wicked, The Wizard Of Oz from the (not quite so) Big Bad's perspective, there are animals and then there are Animals, who talk. Humans and Animals eat animals and use them as beasts of burden.
Daine, the main character in Tamora Pierce's Immortals books, suffers from Carnivore Confusion. She's a "wildmage" who, among other things, can turn into any animal she wants. Before she started to learn about her magic, she grew up eating meat like anybody else, and continued to hunt and eat meat for a long time after discovering it — she says at one point that she doesn't see why this would surprise anybody, since animals kill and eat each other all the time, and it's not as if she kills for sport or uses her magic to lure prey towards her. This changes, however, after a bad experience or two when she herself is pursued in animal form by hunters — game meat becomes Nausea Fuel for her, and she can't stand to eat it anymore, having felt what the animal went through. She doesn't object to it in principle or try to stop other people; she just can't stomach it herself. It's mentioned that she gets by okay with domesticated meat by never bonding mentally with any farm animals, and how she feels about fish or insects isn't mentioned.
The Medieval work the Roman de Renard (the stories of Reynard the Fox) are an early example of this, and probably the major inspiration for Redwall. Although No Cartoon Fish applies, most other animals are sapient and you have a situation where they are ruled by a Lion and other nobility are carnivores but others are herbivores. The logic seems to be that since Aristocrats Are Evil in the real world, it isn't that odd that characters would be perfectly willing to kill and eat their fellow subjects.
While there aren't any talking animals in the Codex Alera (well, there are the Canim, but they're a different species), the Predators Are Mean subtrope is present in full force in Furies of Calderon. The two tribes of Marat who attack the human settlements have predatory Bond Creatures (wolves and terror birds), while the two that eventually ally with the humans have more herbivorous ones (ground sloths and horses).
although in the later books, all the Marat tribes are basically at peace with the Alerans and are all seen trading at the marketplace that was set up for trade between the races.
In The Wild Road, a book where most of the protagonists are feral cats, all or at least most animals can communicate with each other, but they largely befriend only members of their own species, and try not to talk to prey. However, the Majicou has a fox (Loves a Dustbin) and a magpie (One For Sorrow) as comrades, who help the hero of the story, Tag, and his friends, and they form a tight companionship (although Tag and Loves a Dustbin are quicker to become friends than he and One For Sorrow, since the latter taunted Tag in his kittenhood, causing him to try to eat him more than once). The line "You can't eat your friends!" is brought up first by One For Sorrow, then by Tag at the end of the book when One For Sorrow dies, and his last request is for Tag and his friends to eat his body so he can always be with them. They do.
Frequently averted with predatory species in the Star Trek Novel Verse. The Pahkwa-thanh (like Dr. Ree in Star Trek: Titan) have always considered their prey animals sapient. They don't eat humanoids and "civilized" beings, not because they have an objection to it as such, but because it would be rude. Humanoids don't consider themselves part of nature; to eat them would be impolite, which Pahkwa-thanh are not. If you think you're prey, though, they'll happily eat you. The Frills are another more-or-less-friendly race that is happy to eat sapient prey. Both Frills and Pahkwa-thanh are Federation members, and thus allied with the heroes. For a less pleasant sapient-meat eater, there's the Fethetrit. They consider slow consumption of a sapient being, while keeping them alive as long as possible, to be sport.
This seems to be averted in the Warrior Cats series with the cats being the only sentient animals. Dogs are portrayed as dumb brutes; foxes are sly, vicious predators; badgers kill mercilessly; and prey species (rabbits, voles, mice, birds, fish) are unintelligent, so it's okay to eat them. However, in The New Prophecy, it is revealed that other animals also communicate and are somewhat aware. They meet a badger who speaks the cats' language, as well as the languages of foxes and rabbits. You might think this would raise eyebrows about what the cats have been eating all along, but it's stated that, while badgers can be intelligent as a plot device, rabbits are stupid and don't talk about (read: think about) much of anything at all.
Thinking about it, this is present in Twilight, and hence a great many Follow the Leader supernatural novels which feature a vampire dating a human.
In The City by Clifford Simak, the final parts are that Earth is inhabited by sentient dogs (and other creatures), and synthetic meat is provided for the carnivores.
Dealt with in a shockingly matter-of-fact manner in Charlotte's Web. Charlotte is unquestionably a loyal friend to and protector of Wilbur the pig. But she is also a spider, so at the end of the day there's no getting around her cold-blooded willingness to kill smaller creatures for food. She shows Wilbur how she hunts on her web: she bites a fly that has become trapped in the sticky strands, injecting it with venom, and then spins a cocoon around it so that she can store it for a future meal. Wilbur, who has himself been saved from being turned into bacon by Charlotte's efforts, is understandably horrified; he makes Charlotte promise not to eat the fly until after he has left.
Wilbur: You mean... you... eat them?
Charlotte: (very matter-of-factly) Oh no, of course not. I drink their blood. I love blood.
The Harlan Ellison short story "Quicktime", from the anthology Angry Candy, deals with this trope. In a Feudal Future society, Lord Garth escapes an army of rebellious peasants through a time-machine programmed to travel into the early age of dinosaurs. The scientist who invented the time machine assures Lord Garth that he will be safe because the dinosaurs in the time he will be sent are all herbivores and will not eat him. As Lord Garth learns too late, the only way for an herbivorous dinosaur to learn whether something is edible is to bite into it and spit it out if it isn't palatable. He doesn't get eaten, but he's no less dead.
Averted in Cerberon. The intelligent carnivores don't have a problem with eating other intelligent species. As far as they're concerned, meat is meat, regardless of the source. They do avoid outright cannibalism, but eating a half-human hybrid of their own species doesn't seem to count as cannibalism to them.
In A Night in the Lonesome October, the various familiars can all speak to one another and to other animals, yet don't shy away from the prospect of eating fellow animals or even fellow familiars. They even make jokes about it. Justified because it was the only way for predators like Graymalk to survive before finding someone to provide for them, and because they're involved in a Game that makes few allowances for scruples, animal or human.
The picture book First Tomato from the Bunny Planet series by Rosemary Wells describes a group of bunny-people children being served bologna sandwiches, which greatly depresses the main character, as this is her least favorite lunch.
In the picture book Diary of a Spider, the main character makes a few offhand comments about eating smaller bugs ("Butterflies taste better with a little barbecue sauce") and gets a postcard from his grandfather vacationing in Paris declaring that "French bugs are delicious!". What makes this especially odd is that one of his best friends is a talking fly. Even weirder, said fly has an encounter with a much larger spider, who makes no attempt to eat her (he only makes fun of her for eating with her feet). This gets lampshaded when Fly's mom is shown to be afraid of Spider, but still...wuuuuuh?
For the most part the animals in Sonic the Hedgehog in Robotnik's Laboratory all eat junk food like nachos, crisps and pizza (lots and lots of pizza). At one point however Sonic and Tails wish they could be at home with a bucket of chicken. This is despite the that they have a friend who is a chicken. Turns out he's going to be cooked by Dr Robotnik which is of course treated as being evil.
In Dinoverse, kid Time Travel and end up possessing the bodies of various dinosaurs. The "normal" dinosaurs are quite intelligent but non-speaking. Firmly inoculated with Predators Are Mean, Nice Guy Mike, in the body of a Tyrannosaurus rex, reluctantly accepts that he can't go vegetarian and subsists on fish, refusing to even eat carrion unless it was killed by something else. In a later book, Patience, in the body of an Acrocanthusaur, eats carrion without hesitation but refuses to kill a herbivorous dinosaur.
Discussed in Summer in Orcus. Summer meets a talking weasel and a talking bird, and the latter politely but firmly declines to help the weasel find an egg to eat, and Summer finds herself wondering if there are any animals in Orcus that don't talk, "and whether that made it awkward at mealtimes."
William Steig's Doctor De Soto is about a mouse dentist who treats various other anthropomorphic animals, in case of larger creatures by climbing into their mouths. He's wary of treating carnivorous animals, and when a fox with a particularly bad tooth-ache comes to him begging for help, De Soto feels the need to take precautions so the fox doesn't give in to the temptation to eat him once his tooth is fixed.