Xenophobia literally means fear of the strange or foreign. Politically, it is applied as a blanket term for nationalism, racism, tribalism, or any other fear or suspicion of an ingroup towards an outgroup.
Oftentimes, fiction will portray plant-eating species as being rather friendly. But others, often authors who've done their research, will depict intelligent herbivores as xenophobic.
This has basis in reality, many herbivores in real life are the prey of something else, so a variety of different species will react to strange things with a strong flight-or-fight response.
- In Beastars, herbivores tend to regard carnivores with anything from wariness to active hatred. As it's common for predators to murder prey for food or even just hurt them by accident, this attitude is rather justified.
- In Oumagadoki Doubutsuen, one of the villains in the Circus Arc is a stallion-man who's incredibly prejudiced and racist towards carnivores, calling them stupid and brutal, and is show expressing contempt both for Shishido and Uwabami (a lion and a snake) and also for his own comrades Byakkov and Toytoy (a white tiger and a poodle). He immediately takes a liking for Kisazou, an elephant, because he's a "fellow herbivore", but as soon as he see him protecting his carnivore friends he turns hostile and attacks him.
- The Land Before Time has this, with the herbivores even tending to avoid other herbivores before they all ended up in the Great Valley. The narrator even comments on this, mentioning that "there had never been such a herd before" when referring to Littlefoot, an Apatosaurus, and his friends, who consist of a Saurolophus, a Stegosaurus, a Triceratops, and a Pteranodon (the last of these was actually a carnivore in real life.)
- In Zootopia, the Big Bad is able to inflame the historic tension between predators and prey by setting up a conspiracy to cause some predators to "go savage" and then manipulates the prey population's fear of being attacked for their own political ends. The trope is downplayed in that the herbivore population is shown to be quite diverse where some herbivore characters are bold, while others are timid, and others are just citizens reacting to a crisis situation. While the fear of "the other" is at play, the story is more about how a crisis can create a fear that can be manipulated instead of a specific type of citizen (ie herbivores) always being naturally xenophobic.
- The sheep on Farmer Hoggett's farm in Babe have learned to trust the young pig, since he's polite and non-threatening. This stands in contrast to the working dogs Rex and Fly, whom the sheep still call "wolf". It becomes a plot point when Babe is sent to herd blackface sheep that don't trust him, and Rex beseeches the Hoggett sheep for a means to signal the other sheep that Babe can be trusted.
- In Larry Niven's Known Space universe, the Pierson's Puppeteers are grazers primarily motivated by fear and regard all other species with suspicion at best. The only ones who are willing to even leave their homeworld and speak with others are considered insane by their fellows. They're also responsible for a couple of genocides and eugenics experiments on humans and Kzinti.
- In The Jenkinsverse, most sentient alien species are descended from herbivores. As a result, they tend to view any species that consumes meat with either suspicion or dread. This becomes a problem for humans trying to find proper nutrition after their release from abduction, and a bigger problem for humanity as a whole while trying to enter the galactic stage, as the established political powers find our binocular vision and canine teeth horrifying, (meaning a human can't even smile without causing fear) and comparisons to the Always Chaotic Evil Hunters are always being made even long after the Hunters themselves declare humanity their enemy.
- Bravelands: The baboons are initially reluctant to take in Fearless, an abandoned lion cub, until Stinger convinces them that he was gifted to them by their God. As Fearless grows he turns out to be an asset that deflects predators and rivals from the troop. Despite this, he is never completely considered a part of the troop. Fearless ends up kicked out when the new, conservative and xenophobic leader decides he's too dangerous.
- The rabbits in Watership Down really don't trust any other lifeform, up to and including unfamiliar rabbits. They're not necessarily aggressive about it, much preferring to run and hide than fight, but that's mostly because they're not really equipped for combat- if they do run across something they can kill, and it's not easier to run, they'll kill it without too much thought. Their entire mythology as presented in the book centers around them being a kind of designated Hate Sink for the animal kingdom. Not that this is entirely justified, seeing as almost everything they come across does try to kill them.
- In Traveller, the K'kree Empire is determined to eradicate all carnivores and convert omnivores to vegetarianism (or else). Fortunately, their other neuroses such as claustrophobia, monophobia, and resistance to change have limited their expansion.note
- In In Our Shadow rats are so afraid of everything that they cannot tolerate the presence of other species that haven't been cowed into submission. In their empire's home territories this is accomplished by a "submission signal" while on the rest of the planet they use good old-fashioned military force enabled by their technological advantage. When the lemurs get access to human mechs that can fight their machines the rats literally wipe Madagascar off the map. However, it's later discovered that Emperor Schorl uses a "fear signal" to amplify rat xenophobia as a means of controlling them.
- To most herbivores, anything they're not familiar with is a potential threat to themselves or their young. Smaller herbivores will typically try to run from larger potential predators, while larger herbivores might not react or they might take action to eliminate the potential threat to their offspring.
- Horses need to be trained very extensively not to spook at surprises, horses trained for combat situations especially so. And even then they'll instinctively kick anything that walks up behind them.
- Many small pets, such as budgies and mice, need to be hand-tamed (which depending on the individual animal can be quite a task). They're little prey animals so humans are instinctively dangerous to them.
- Hippos take this to an extreme. They may only eat plants, but they are also extremely aggressive, territorial, and their jaws can bite a crocodile in half. Oh, and they can easily outrun humans, even on land. It's telling that Steve Irwin, who famously considered wrestling with crocodiles fun and regularly handled extremely venomous creatures, considered the most dangerous thing he ever did to be crossing a river full of hippos.