Dr. Zaius: Then answer me this — if man was superior, why didn't he survive?
In the distant future (or at least 20 Minutes into the Future), humanity has declined, and animals (whether all of them, or a few certain kinds) become the new dominant species.
Here, the humans might be extinct and animals now roam the world freely; there might be scenes of them living on manmade living places if any of them existed at all. Alternatively, there might be only a few humans left, either scattered away or confined to a single location. They may have regressed (whether just culturally or outright becoming animals themselves) so that they can't form a modern-like society anymore; they're no longer the dominant species. In some examples, humanity instead is getting along just fine, with the new species simply coexisting alongside them.
Sometimes, the animals might have become Funny Animals or Beast Men (which one it is depends on whether the work leans more to the comedic side and uses this trope to justify a World of Funny Animals setting or whether it leans more to the drama side and uses this trope to speculate a hypothetical future for social commentary). There may or may not be an in-universe "evolution" happening to them; here they have quite literally become the new "man". Furthering in this direction, the humanoid animals may even see the humans (if there are any) as "animals", either as a Human Pet, human cattle, etc.
Plots involving this setting might be about how animals live now that they're the dominant species, or they may focus on the few humans who tried to survive in the "new world" full of animals.
It's generally accepted that, if humanity were to go extinct (or even if they didn't), given enough time, another species could rise to the task of attaining human-level sentience. However, the idea that a humanoid body plan is a necessary requirement for this to come to pass has come under increased scrutiny in recent years; in all likelihood, a species that gained intelligence equal to humanity would likely look not too dissimilar to its ancestors. Just as humans and the other great apes share common features, a sapient bird, for example, would probably still resemble whichever avian family it came from.
See also Uplifted Animal, which is how the animals become smarter.
- Sonic the Hedgehog (Archie Comics) says that the planet Mobius is actually Earth in the future. The alien Xordas dropped gene-bombs on it intending to devolve but uplifted the animals into Funny Animals as well.
- In Kamandi, the Last Boy on Earth, a great disaster killed off nearly all humans, with the few survivors lacking intelligence. In the meantime, races of humanoid animals rose up to take the humans' place on the food chain.
- A story in Doctor Who Magazine has a Jerkass billionaire travelling back in time with a hunting party to prehistoric times to kill animals extinct in the present, beleiving that travelling back in time makes them part of history, and thus unable to change it. After he almost wipes out a primitive mammal, a party of humanoid reptiles come back from the same era - an alternate version that ensued as a result of his actions going off successfully.
- Don Lawrence's Storm is similar to Planet of the Apes except the time travelling astronaut returns to find Earth controlled by Fish People.
- Superman: An old Silver Age issue involves a species of super-intelligent giant ants from another planet, who were mutated by a nuclear war that wiped out the humans of their world. And yes, they're called humans, specifically, by the ants!
- In My Cage, humans are long extinct and the world is populated by civilized anthropomorphic animals of various species. Although the characters are aware humans once existed, the strip's focus on workplace humour means the reason for their extinction never comes up.
- Rock and Rule occurs on an Earth where humanity eradicated itself, leaving the dogs, cats and rats to ascend mastery of the world. It seems they can now interbreed, as none of the characters seem to fit neatly into canine, feline or murine physiology.
- Superfly's plan in Teenage Mutant Ninja Turtles: Mutant Mayhem is to release ooze into the atmosphere, killing most of humanity and uplifting every animal into a mutant. He's taking suggestions on what to do with the remaining humans. Food and slavery were his best ideas.
- All Tomorrows: While focusing mostly on Human Subspecies, one race noted descended from a type of lizard formerly kept as livestock which eventually became sapient, while the humans which farmed them eventually become completely bestial and themselves became livestock to the lizards. While the Saurosapients descended from completely non-human ancestors, they were considered human for all intents and purposes.
- Baaa, a picture book by David Macaulay, has sheep gain sentience and take over the world after mankind dies out. Their society quickly develops a lot of the same problems that drove human society extinct, with overpopulation, poverty, and a severe food shortage. Fortunately, the sheep leaders develop a new food product called "Baaa" that conveniently solves all three of those problems at once... Eventually, this drives the sheep extinct as well.
- The characters of "Later Than You Think", by Fritz Leiber, appear to be extraterrestrials discussing the remains of human civilization on our Earth, but they're actually studying the ruins of a rat civilization to which humans are Precursors.
- Andre Norton's A Breed To Come has cats that live like tribal humans after humans fled Earth following environmental disaster. Descendants of dogs, pigs and rats are also sentient.
- City by Clifford Simak has two replacements for humanity, dogs and ants.
- "No Connection", by Isaac Asimov, takes place on an Earth where humanity went extinct. America is populated by a peaceful bear-descended race. The story ends with them expecting a conflict with ape-descended aggressors from Eurasia.
- "Null P", by William Tenn, sees dogs take over the Earth. Humans still exist, but they have given up civilization and it isn't even clear if they are sapient. They are adopted as pets by the dogs and later go effectively extinct.
- George Orwell's Animal Farm has a localized version of this, where the livestock overthrow the human owners of Manor Farm and establish a society where the animals are in charge. It becomes a Literal Metaphor by the end, where the pigs, the leaders of the revolution who by that point have sold out their ideals in favor of maintaining an iron grip on power, have become virtually indistinguishable from humans. Orwell intended it as a Roman à Clef satire of the trajectory of the Russian Revolution, with the pigs' leader Napoleon serving as a direct analogue to Josef Stalin.
- Save the Human, a book by David Wood and Tony Husband, depicts a future in which humans nearly became extinct as a result of their wars and pollution. Now the animals are in charge, and some keep humans as pets... or to perform experiments on.
- Weg der Erde (Path Of the Earth) by Reinhard Köhrer, describes how a rag-tag group of terrestrial sentients travel forwards in time, starting with a human female, later joined by on of the intelligent lizards and then evolved insects, to stop their time machine in the age of humanoid birds, billion years hence. The human and the lizard find some closure, it’s implied that the insect will lay eggs and thus two intelligent species will inhabit earth.
- In Red Dwarf, while Lister was in stasis a radiation leak killed every other human on board the Red Dwarf and his cat's descendants evolved into a civilization of sapient humanoids in the cargo hold who worshiped him as a god. By the time Lister wakes up three million years later, the cats have fought a holy war over the color of his hat and left the ship, leaving behind a few infirm or idiotic who gradually died off until there was only one left on board.
- Saturday Night Live had a series of sketches called "Bear City" in which a meteor strikes an American city, driving the human population underground and allowing the bears to rise up and fill the roles formerly filled by humans. The sketches are notable in that the humor is driven entirely through action as the bears cannot talk.
- Mr. Meaty: In "Suburb of the Apes", Josh and Parker attempt to travel two months into the future to get a new game console. They accidentally end up in the 27th century, where a race of baboons have taken over the planet, the mall is an overgrown ruin and the only signs of humanity besides the duo are the skeletons littering the place.
- After the Bomb: A nuclear or biological war (depending on the edition) kills off most of the human race but mutates a wide range of other animals to human-level intelligence.
- Hc Svnt Dracones features the corporate colonies on Mars mass-producing human-animal hybrids called "Vectors" to repopulate the solar system after the Earth is destroyed by a nuclear war. In the successive centuries baseline humanity gradually goes extinct.
- Pugmire is set in a pseudo-medieval kingdom populated by uplifted dogs after humanity's mysterious disappearance.
- At least some areas of Gamma World are like this, with Uplifted Animal factions dominating society and humans (mutant or otherwise) either degenerated to primitivism or absent altogether.
- Inherit the Earth is a seemingly medieval world populated by sentient bipedal animals whose ancestors were uplifted by humanity before a plague wiped them out.
- Killer Instinct: In Riptor's ending in the original game, the genetic experiments Ultratech used to create Riptor end up dooming humanity and ushering in a second era of the dinosaurs.
- Little Tail Bronx: The setting (where Tail Concerto, Solatorobo: Red the Hunter and Fuga: Melodies of Steel take place) is set thousands of years after humankind went extinct and was replaced by the Caninu (anthropomorphic dogs) and Felineko (anthropomorphic cats). A Japan-only artbook for Solatorobo explains that prior to the end of the "Old World", the Australian government organized a team of researchers known as the "XII Owls" to study the strange "Juno" machines scattered across the planet, and this team was given several dogs and cats to raise for the purposes of maintaining mental health and morale. Yurlungur— an AI personality born from Australia's own natural Juno— assumed that this was purely an act of love on the humans' part, hence why she chose dogs and cats to be humankind's successors following the "Reset" that restarted all life on the planet.
- Paladog: After humanity is destroyed for its wickedness, animals take over to replace them.
- Pokémon Black and White 2: One of the in-universe movies you can make at Pokestar Studios involves the protagonists accidentally time-travelling to a distant future where Pokémon rule the world and capture humans to battle with.
- Portal 2: One public service announcement (made with the knowledge that test subjects like Chell may have been in stasis long enough for civilization to have collapsed) warns about a potential "animal king" ruling the earth that humans could not reason with. Said animal king is represented by a giant Turret with leopard skin textures and a crown lording over tiny humans in a UN-esque amphitheater.
- Splatoon takes place in a world where marine animals have become the dominant species on Earth due to rising sea levels and global conflict driving humanity to extinction thousands of years prior. Splatoon 3 takes this even more literally by revealing that the animals that reclaimed Earth developed sapience after absorbing special liquid crystals which contained the last of humanity's memories and desires.
- Timberborn: The game is set long after the extinction of humanity. In its wake, beavers have developed sapience and a newly industrial civilization, and begin to stake out their own claim on the world.
- Tokyo Jungle is set in a world in which there are no humans, the city of Tokyo is falling into disrepair without any maintenance, and a new ecosystem is forming in its ruins where multiple species of herbivores and carnivores compete for survival. The cause of this is eventually revealed to be humans from an apocalyptic future attempting to transplant themselves back to the 21st century with time travel, creating a Time Paradox which causes all present-day humans to vanish.
- Utawarerumono: It's implied that the surface was made uninhabitable for a time and the surviving humans fled into sterile underground shelters. However, generations underground decayed their immune systems and when the surface had recovered, they could no longer return to it. The half-human hybrids populating the planet actually descend from a vast series of genetic experimentation projects that were undertaken in a hidden underground lab, apparently as part of a project to reclaim the uninhabitable Earth above. The only remaining humans are Hakuowlo and the Tatari, who were transformed into their current forms by the aforementioned Hakuowlo as punishment for dissecting his wife and child.
- Blade of Toshubi is set on a future Earth where a nano-virus was used in World War IV to rid the Earth's surface of humans — the virus is also believed to have caused the mutation of animals to a sentient, humanoid form. The reader finds out that not all humans died when World War IV changed the world — there are four arks of humans in orbit waiting for the nano-virus to reach safe levels to return.
- Forest Hill takes place in a distant future resembling the 1990's. Humans disappeared in the distant past and took much of their technology with them — various religions have formed around the expectation that humanity will return.
- In Our Shadow takes place 50,000 years after a hyper-advanced human civilization apparently wiped itself out and left their hyper-advanced technology all over the globe, including caches of weapons under stasis fields with only a few intelligence tests locking them up. In the interceding millennia many species of animal that had grasping appendages evolved rapidly in response to the variety of artifacts left behind by humanity, developing sapience even. It is later revealed in the stinger of Book 1 that a human ship has been circling the solar system for millennia, and is now coming back after detecting the flare used by Bray.
- In Jack (David Hopkins), the world used to belong to humanity. That was until Jack killed them all, giving rise to the furry race.
- Tamberlane takes place in a world where Funny Animals overthrew/replaced humanity centuries ago. The protagonist is a human child who finds herself in a world that has completely forgotten what humans looked like and that they weren't just myths.
- Unity takes place on a massive Generation Ship where the humans who originally crewed it seem to have gone extinct while the fauna evolved sapience in various ways. The main character is distantly descended from the platypus.
- On The Comics Curmudgeon, one of Josh's Running Gags is to interpret Slylock Fox as being set in the wake of the "animapocalypse". Apparently, all of Earth's animals mysteriously gained sentience on a single fateful day, then killed off most of humanity and hijacked human civilization.
- In SCP Foundation, the Foundation labels such an event as an "SK-class dominance shift scenario" and actively works to intercept anything with the potential to cause it. It's revealed that we inverted this with Bigfoot and supplanted them as the dominant species on Earth, with the Foundation higher-ups living in fear of them one day attempting to return the favor.
- Batman: The Brave and the Bold: In "The Last Bat On Earth", Batman chases Gorilla Grodd to Kamandi's future (see above in comics), with Grodd's plotting to conquer the other evolved animals with both his new Gorilla army and Twenty-First Century technology.
- Futurama: Earth undergoes such a change in dominant species in the future in "The Late Philip J. Fry". Several times over, as a matter of fact — after the apes take over, birds displace them, then cows displace the birds and then some sort of slug creatures displace the cows, as Fry realizes when seeing a series of ruined Statues of Liberty each modeled after a former dominant species.
- Peace on Earth takes place After the End, where animals have become intelligent and taken over the world after humans killed each other down to the last man in an apocalyptic global war. A 1955 remake (Good Will to Men) would change the exact cause to nuclear war.
- Rick and Morty: In "Lawnmower Dog", Rick creates a device that makes the family dog, Snuffles, intelligent. Unfortunately, Snuffles becomes too intelligent and ends up making every dog in the world smart and they take over the Earth. Good thing Rick and Morty saved the day... For now, at least.
- Word of God says that if Sonic the Hedgehog (SatAM) had lasted a third season, we would have found out that Mobius was a future Earth following a nuclear war that ended humanity, and the fallout would have accidentally uplifted the animals into becoming intelligent humanoids. An altered version of this backstory was used in Sonic the Hedgehog (Archie Comics).