A common way to use pets in stories is to get us all emotionally attached to them… and then kill them off. And then we all hate you for it because WHY? How dare you kill off Fido! Pets have been introduced and killed off in nearly every book I’ve read or movie I’ve watched, and it’s always sad. Obviously this is a great way to evoke emotion from readers, but what if–what if–I told you that you could let the pet live? No really, you can do that.
Pets can be more than just your twisted idea of a sad chapter to bum out the protagonist (and the rest of us). They can do so much more for the plot line and your MC.
In the high fantasy I’m working on, one of my characters has a wolf who she often leans on for support in difficult times. He is her comfort and safety net. Without him she feels alone. Having an animal who is important to the protagonist in such a way can really give them the courage to face all the conflict ahead of them in the story–especially when separated from the pet at times when they need the pet to be brave.
Animal senses can also be implemented into the story to provide little hints, such as a dog growling or barking at a character who is revealed to belong to the dark side later, or a horse who gets skittish in certain parts of a forest rumoured to be cursed.
Pets can warn characters of danger or stop them from doing something dangerous. Instead of the MC risking their life fighting the minor thugs of the story, the pet can protect them instead. This shouldn’t be used as a crutch, but it can be used at the start of the story–before development–to establish the trust between human and pet. (Later, the MC must be able to stand on their own to show how far they’ve come.)
Not all animals can be on the protagonist’s side, of course. In Rise of the Planet of the Apes, humans clash against the apes in battle, and in The Hunger Games, animal-like creatures try to take a bite out of the heroes.
Just be careful what you write where animals are concerned (or violence in general). No one wants to read about animal cruelty. It isn’t cool and it certainly isn’t entertaining, and you’ll find your story being thrown aside pretty rapidly. But, of course, I shouldn’t need to point this out… unless you’re the kind of monster who grins the whole way through Marley and Me.