History Main / FormerlySapientSpecies

** The first sapient species to appear on the planet was the fork-tailed babbling jays, a species of intelligent songbird. However, changing climates would kill off most of the species thanks to increased rainfall leading to disease growth in their once desert home. Out of shear loneliness, the last surviving babbling jay would take a mate from a closely related but nonsapient species and produce hybrid children that also lacked his intellect (save for a young grandchild who was killed by a predatory bird when their intelligence distracted them). Millions of years later these hybrid descendants would live on in the chatterers, a nonsapient but still fairly intelligent bird that can mimic speech. Five million years later, the chatter's descendant, the bluetailed chatteraven, have become near-sapient but are still aggressive and instinct driven in their behavior. However, one bluetail named Brighteye is born with a genetic mutation that makes him fully sapient but only as a throwback to the babbling jays rather than the first of a new sapient species.

** Gravediggers are lineage of sapient, quadrupedal, tool-using birds that developed various offshoot species over time. Savage gravediggers are descendants of the tundra gravedigger populations forced towards the southern coast during the Ultimocene glaciation. The extremely harsh environments where they evolved and now live produced a strong selection against higher intelligence, as the lack of useful building materials following the extinction of forest environments provided little benefit for tool use and the scarcity of food made big, energy-hungry brains a liability. As a result, they're only about as bright as a chimp and have lost all forms of tool use, empathy, and culture.
** The first sapient species to appear on the planet was the fork-tailed babbling jays, a species of intelligent songbird. However, changing climates would kill off most of the species thanks to increased rainfall leading to disease growth in their once desert home. Out of shear loneliness, the last surviving babbling jay would take a mate from a closely related but nonsapient species and produce hybrid children that also lacked his intellect (save for a young grandchild who was killed by a predatory bird when their intelligence distracted them). Millions of years later these hybrid descendants would live on in the chatterers, a nonsapient but still fairly intelligent bird that can mimic speech. Five million years later, the chatter's descendant, the bluetailed chatteraven, have become near-sapient but are still aggressive and instinct driven in their behavior. However, one bluetail named Brighteye is born with a genetic mutation that makes him fully sapient but only as a throwback to the babbling jays rather than the first of a new sapient species.

* ''Literature/TheChroniclesOfNarnia'': Talking beasts can revert back to dumb animals if they go back to their ways. Most notable in ''Literature/TheLastBattle'', where the cat Ginger is literally scared out of his wits when he unexpectedly encounters [[{{Satan}} Tash]].[[labelnote: *]]Ginger didn't believe in either Tash or [[{{Jesus}} Aslan]], but had made a show of calling on "Tashlan" to manipulate the other animals. [[GoneHorriblyRight It worked.]][[/labelnote]]

* A short story by Creator/PhilipJoseFarmer has a human adventurer discovering a parellel world where cannibalism is not only permitted, it is big business. This world lacks cattle or pigs - they are completely unknown - and not knowing this, the visitor seeks to blend in by getting a farm labourer's job dealing with livestock. He discovers the "livestock" are a mutated form of human beings, with the intelligence and self-awareness of cows. As they take the form of not unattractive women bred for milk and eventually meat, this causes [[BestialityIsDepraved lots of problems]]. And a sense of [[TeenyWeenie inadequacy]] when he has to manage the "bull".

* ''Literature/TheChroniclesOfNarnia'': Talking beasts can revert back to dumb animals if they go back to their ways. Most notable in ''Literature/TheLastBattle'', where the cat Ginger is literally scared out of his wits when he unexpectedly encounters [[{{Satan}} Tash]].[[labelnote: *]]Ginger didn't believe in either Tash or [[{{Jesus}} Aslan]], but had made a show of calling on "Tashlan" to manipulate the other animals. [[GoneHorriblyRight It worked.]][[/labelnote]]

* A downplayed example with the thoriphants in ''Film/{{Mosley}}'', where the protagonist species are a degraded relic of their kind, once upright and with prehensile hands but now reduced to quadrupedal beasts of burden enslaved by humans. Downplayed in that they do retain their sapience and can speak to humans just fine, it's just HumansAreBastards and have no qualms about treating these clearly sapient creatures like mere livestock.

* ''Wiki/SCPFoundation'': SCP-1000 ([[IHaveManyNames also known as]] {{Bigfoot}}, the Sasquatch, the Yeti, and more) was [[{{Precursors}} the dominant species on Earth long before recorded history]], every bit as advanced and intelligent as we are now if not more so. Eventually though, humanity arose to [[FinalSolution wipe out almost all of them]], and then used their own advanced technology to [[DevolutionDevice reduce the intelligence of the survivors to that of apes]], before destroying almost all evidence of their existence, including humanity's own memories of them. However, in recent times their intelligence has begun to return, and [[{{Ultraterrestrials}} they seem to want their place on Earth back]].

** In "[[Recap/DoctorWhoS29E3Gridlock Gridlock]]", the Macra, who appeared in the original series serial "[[Recap/DoctorWhoS4E7TheMacraTerror The Macra Terror]]" as cunning behind-the-scenes manipulators, are shown to have devolved into mindless beasts many centuries into the future.

The result of this is a creature, usually a human, that lost its self-awareness and higher intelligence and become a simple beast. Depending on the setting, this may be the extent of the modifications or the creature may also display any degree of physical changes -- fur, increased or decreased size, altered proportions, claws and fangs, or anything else pertaining to whichever ecological niche it now fills. The most common version is a creature resembling a non-human primate or a FrazettaMan in appearance and behavior, but it's not entirely uncommon to see humans transformed into aquatic, seal- or whale-like creatures.

* A short story by Creator/PhilipJoseFarmer has a human adventurer discovering a parellel world where cannibalism is not only permitted, it is big business. This world lacks cattle or pigs - they are completely unknown - and not knowing this, the visitor seeks to blend in by getting a farm labourer's job dealing with livestock. He discovers the "livestock" are a mutated form of human beings, with the intelligence and self-awareness of cows. As they take the form of not unattractive women bred for milk and eventually meat, this causes [[BestialityIsDepraved lots of problems]]. And [[a sense of TeenyWeenie inadequacy]] when he has to manage the "bull".

* A short story by Creator/PhilipJoseFarmer has a human adventurer discovering a parellel world where cannibalism is not only permitted, it is big business. This world lacks cattle or pigs - they are completely unknown - and not knowing this, the visitor seeks to blend in by getting a farm labourer's job dealing with livestock. He discovers the "livestock" are a mutated form of human beings, with the intelligence and self-awareness of cows. As they take the form of not unattractive women bred for milk and eventually meat, this causes lots of problems. And a sense of inadequacy when he has to manage the "bull".

* ''Literature/TheWarAgainstTheChtorr'': This appears to be the place that humans will eventually fill once the Earth is transformed to a completely Chtorran ecology. There are herds of humans in some of the ruined cities that are no longer sapient, and being around them too much can somehow draw other humans into joining them. Its uncertain whether an infectious agent is involved or something else. The fourth book reveals that [[spoiler:the "bunnydogs" and "libbits" mistaken for Chtorran lifeforms are in fact transformed human children or their descendants. In the Chtorran ecology they are non-sapient fast-breeding cattle.]] There are hints that some of the Chtorran lifeforms were also once more sapient than they are now.

** [[VideoGameCrueltyPotential You can inflict this]] on other species via the biological ascension tree- modifying a species to add the Nerve Stapled trait essentially turns them into unthinking labor drones. For added sadism you can add the Delicious trait, literally reducing them to livestock.

* ''Literature/{{Ringworld}}'': When the Pak Protectors built the Ringworld, they introduced no animal life to it beyond their own kind, some food animals and microfauna. As such, when the Pak empire collapsed and the Pak Breeders (''Homo habilis'') were left on their own, the Breeders radiated to fill the various empty niches in the massive world they found themselves in. Many of their descendants are now sapient, but others -- such as the predatory vampires -- remain little more than cunning animals.
** ''Literature/KnownSpace'': This happens several times in Known Space as a whole. The Humans are a LostColony of Pak, on a planet unable to sustain the virus in the Tree of Life necessary for the transformation to Protector. As a result, after the first generation of Protectors died, Earth humans were no longer being bred along clan lines by Protectors and thus mutated and evolved to form the various Homminds. Even further back, the Slavers (aka Thrintun) had formed a large empire, despite being fairly stupid, because of their vast psychic powers let them control much smarter species. During a rebellion caused by a smarter species developing a psychic shield, the Thrintun cause a galaxy wide mass extinction able to kill anything with a backbone. Except other Thrintun. The Grog are believed to be surviving Slavers who have become mostly unsapient.

-> ''"Reject humanity, return to monke."''
-->-- ''An anarcho-primitivism [[MemeticMutation internet meme]] evoking this trope''

** The first sapient species to appear on the planet was the folk-tailed babbling jays, a species of intelligent songbird. However, changing climates would kill off most of the species thanks to increased rainfall leading to disease growth in their once desert home. Out of shear loneliness, the last surviving babbling jay would take a mate from a closely related but nonsapient species and produce hybrid children that also lacked his intellect (save for a young grandchild who was killed by a predatory bird when their intelligence distracted them). Millions of years later these hybrid descendants would live on in the chatterers, a nonsapient but still fairly intelligent bird that can mimic speech.

* ''Series/WaywardPines'': The majority of humans has devolved into predatory animals known as "abnormals" or "abbies".

** Gravediggers are lineage of sapient, quadrupedal, tool-using birds that developed various offshoot species over time. Savage gravediggers are descendants of the tundra gravedigger populations forced towards the southern coast during the Ultimocene glaciation. The extremely harsh environments where they evolved and now live produced a strong selection against higher intelligence, as the lack of useful building materials following the extinction of forest environments provided little benefit for tool use and the scarcity of food made big, energy-hungry brains a liability. As a result, they're only about as bright as a chimp and have lost all forms of too use, empathy, and culture.

* In the ''TabletopGame/RedDwarf'' game, universes where rabbits evolve intelligence, humans became savages that are mainly used in medical experiments by the rabbits.

** The Kroot, a sort-of avian, humanoid alien species, are able to taste individual parts of the DNA they eat [[LEGOGenetics and incorporate them into themselves]], and their Shapers can direct their kin to eat primarily certain species so as to ensure genetic traits will be passed on to the next generation of Kroot. This often leads to specialized variations on the average Kroot body plan, but continuously eating too much of certain species risks a permanent regression to a bestial state. Several subspecies have been formed this way, like the vaguely-canine Kroothounds, apelike Krootoxen, and carnosaurid Knarlocs, which are now used as beasts of burden and battle.