Cats and dogs are also useful for drawing a character out.

 A lot of people talk to their animals. This gives the writer the chance to let their character verbalise an argument or opinion. You can note temper or reflectiveness of the person as they speak . The animals attentiveness, or not, can also influence how the person finishes the one sided conversation.

The death of an animal can create the opportunity to define a character. If the protagonist shows a negative attitude to the death of the main characters pet is defines differences between them. If they show a positive attitude, it can be used to soften the character and increase the impact of their later actions. A person that likes animals but beats people up indicates a certain mind set.