Animal Cruelty is Just Wrong

When it comes to for a probably of having a psychopath in the making, animals are often among the first targets. However, that’s not the case in this trope, where even the Big Bad guy would be upset if an animal got hurt by another person that didn't deserve it. While allowing nature to take its course on harming animals is one thing, for many who fall under this trope… as far as they’re aware of, nature is the only allowed to hurt animals since they understand about survival. Many characters would often restrict their killings of animals to either put the creature out of its misery, for food only, and/or defense… some would refuse to hurt animals -- period.

Compare to Zombie Advocate, where someone fights for the rights of non-humans. This trope is about characters who despise those who would willfully hurt an animal. It can also be part of Even Evil Has Standards since for some, if the creature doesn’t have a say, they’re could be viewed as defenseless and would leave the animal alone. This is similar to Wouldn't Hurt a Child because of the same belief on never going after the weak.

There are some Truth in Television as some criminal organization does have rules regarding animals and won't tolerate those who are cruel to them. Animal Rights groups like PETA often advocates the end to the cruelty of animals. Some courties even have laws regarding animals, that date back to Anicent Egypt, where those who killed a cat and/or dog on purpose were sent to death.

Compare with Pet the Dog, where an anti-hero or villain does something good for society, perhaps making sure an innocent animal is out of harm's way.

Contrast with Kick the Dog...

Shoot the Dog, where someone is forced to a questionable act because it had to be done.

Anime and Manga
""It's one thing to take people prisoner and threaten them, but when you hurt somebody, that's going too far.""
 * Elfen Lied: Lucy attacks a group of bullies for killing a puppy. The bullies did it out of pure amusement, only for them to learn it was Lucy's Berserk Button... the hard way.
 * While Team Rocket would find ways to kidnaps Pokemon creatures from others, they were shocked to see how Chimchar was treated during his time with Paul for his training regime.
 * Sonic X, Considering the fact he kidnaps animals, Dr. Eggman does have some respect for them.

Film

 * The goal of Elle Woods in the second Legally Blonde is introducing a ban on animal testing.
 * In Free Willy, Jesse, a delinquent, plans to rescue the title character upon learning what the marina was planning to do the capture killer whale.

Literature

 * In Animal Farm, it somewhat inverted as it’s the animals who had with the cruelty under the control of Farmer Jones.
 * The Berenstain Bears and the Bully: Sister Bear gets into a fight with Tuffy when she catches her attacking a baby bird.
 * In Charlotte's Web, Wilbur, the runt of a little of piglets, is spared from slaughter by the daughter of the farmer, who was about to do the deed. To be fair, John, the farmer in question, thought Wilbur had a very slim chance of survival and was going to put him out of his misery, but Fern, the daughter, disagrees.
 * In Crime and Punishment, Raskolnikov recalls the time he witness the beating of a mare horse when he was a child and was very upset about.

Live-Action TV

 * The Blacklist: Raymond "Red" Reddington may still have villainous traits despite his willingness to reform, but even he has a soft-side for animals.
 * The Sopranos: Animal cruelty just so happened to be the Berserk Button of Tony Soprano. learns this one the hard way . For Tony,  Screw the money, He Has Rules.
 * In the Law & Order: Special Victims Unit episode, Born Psychopath, badass of a cop that Fin Tutuola happens to be make a grim discovery when Toby asks for the fate of his dog, Snowball. After seeing that, Tutuola was livid and knows he couldn’t spare Toby the heartbreaking news, but serenely inform both him and his father to exit the apartment, knowing if Henry was , chances are high they could be next.
 * For Myth Busters, while insects that are destined for death by science is allowed, following the microwave poodle myth, the crew decided that it was ones of those myth best to remain an urban legend. Since then, they are a strict policy on using dummies in place of actual animals if harm is likely to be the end result. Only in myths where animals are mostly likely to be unharmed where an actual animal can be used.
 * It was doubled subverted in the Elephants Scared of Mice myth, where actual mice were place in with elephants at a Wildlife Preserve for research purpose. When a mouse was present after the elephant dung used to hide was removed, the elephants just simply moved to the other way from where they were going. Thinking it was just the movement of the dung, it was repeated without the mouse but the elephants just went on their merry way, much to the surprise of Adam and Jamie.
 * Little House on the Prairie episode, Bunny, Laura is outraged on how Nellie treated a horse named Bunny with such cruelty.

Professional Wrestling

 * If you're seen assaulting an animal or anyone dress like one, expect the Dudley Boyz to get the tables and have you threw into them. Diego of Los Matadores found this out the hard way.

Theatre

 * In Equus, a psychiatrist named Martin Dysart is called to investigate a case of a teenager blinding horses. Dysart was told the teenager, Alan Strang, is likely mentally disturbed.

Video Games

 * In The Legend of Zelda, if you attack a chicken, a flock of them would arrive to fight back.
 * In Metal Gear Solid 2: Sons of Liberty, if you have Raiden attack birds, Rose will call him out on it.
 * In the second Boarderlands game, Brick is angered by the torture death of his pet dog, the Vault Hunter has the option of Side-Missions involving going to Lynchwood to track down the Sheriff and her marshals who carried out the deed. After the Wildlife Mission in the Story-Mode,
 * In Call of Duty 4: Modern Warfare, if you attack a dog, a pack of other dogs will attack the shooter, much like in the Zelda's example.

Western Animation

 * The Simpsons: Lisa is a strict vegetarian, though in the video game version she does allow Bart to attack an army of Mutant Dolphin since it was on the grounds of defense. In the series, Lisa's a devoted environmentalist and very strict on animal rights, including being a member of PETA.
 * Bart is the same way, but downplayed because he’s only cruel to insects. However, his Berserk Button includes anyone who dares harm any animals in his presence that are above insects, especially his dog, Santa's Little Helper. Had he not been armed, Mr. Burns would’ve learned the hard way.
 * Doubled Subverted on Maggie in the film, where Krusty orders Mr. Teeny to go after her once they entered in the Simpsons’ house, only for Maggie to break a bottle in order to use as a weapon. She only backs off from any attack when Teeny runs back to Krusty after seeing that Maggie isn't as defenseless as both he and Krusty thought.