Animals in fiction have always left an impression on readers, from the Cheshire Cat in Alice in Wonderland to the tragic story of Old Yeller. They're friends and companions, show human nature, teach life lessons, or simply cause mischief with riddles and disappearing bodies. How to keep animals from becoming part of the background? How can you make them interesting characters? Make them as unique and full of personality as the human characters. Give them time to shine and time to bond with the other characters so that an attachment can be formed.

Often animal characters are personified. When animals are able to talk, they're often given bantering dialogue and a brisk attitude. They usually fill the role of a guide or a sarcastic counterpart. Salem from Sabrina has several human attributes and causes a lot of mischief. When developing animal characters, it's good to remember that they're restricted in the way they move, and what sounds they'll make.

Readers need to be able to form a connection with them. Make them grouchy or playful. Make them the protagonist's best friends. Where the Red Fern Grows has two dogs that never speak, but their deaths are heartbreaking because they were Billy's friends and companions that protected him until the end. They have separate and distinct personalities. The human characters' emotional connections can play a large part in how readers are able to build an attachment to them.

For talking animals, keep their dialogue fitting to their character. If they're grouchy, you can make them blunt and snarky with attitude. Maybe they have a short attention span. This would work really well with dogs, which get distracted easily. Keep the dialogue true to the type of animal they are. What would a cat say that a frog wouldn't? A cat would more likely have an attitude and a high maintenance quality whereas a frog wouldn't. It'll also be good to ask yourself why the animals talk? Do they all talk in this world or only a certain few? They'll have their own mythology and way of life that you'll need to develop. What do they believe in, and what sort of advice would they give?

Try basing the behavior of the animals off your own pets or an animal that you know well. For any sort of wildlife, or an animal you don't have much experience with, research the animals from how they hunt to where they live. Know what conditions they couldn't live in, what they can and can't eat, how they groom, and what their social interaction with like species and other species consists of. Try visualizing the world that animals belong to. If they're a prey species, they would be more cautious about the world. If they're predators, then think about what would frighten them or maybe they react pompously toward their surroundings.

Let the human characters learn a lesson from the animals. The animal can lead the protagonist on their journey as a guide or a mentor. Or go the opposite way and have the animal be more of a lovable nuisance. Whatever the relationship, the animal needs to be likable. Though, just because there's an animal in your story doesn't mean the animal has to be good. If the animal is the villain of the story, then they don't have to be likable, but they need to be believable in how they'd attack.