Can a person be a “that,” and is your dog an “it” or a “she”?
“Who” or “That” for Pets
The Associated Press provides useful guidance about animals, presumably because their writers find themselves writing about pets often enough to need clarification. The AP Stylebook recommends using the pronouns “it” and “that” for animals unless you know the animal’s sex or the animal has a name.
For example, if you were writing about a cat and you didn’t know much about it, you’d write something like “The cat that was stuck in the tree peed on the firefighters.”
If the cat had a name, you’d write something like “Fluffy, the cat who was stuck in the tree, peed on the firefighters.”
If you only knew that it was a female or you were just using pronouns, you’d write something like “The cat who was stuck in the tree meowed at her owner.”
Again, we have style issues to deal with. For example, APA style has different recommendations. They want you to always use “that” when you refer to animals such as cats and rats, not “who.” This is just a guess, but I wonder whether the APA might stick with “that” for animals because, unlike Associated Press writers, APA writers are most often writing about lab animals instead of pets. Regardless, it’s important to remember that even though the general rules are flexible, the rules may be more rigid if you’re following a specific style guide, so be sure to check.
Next: When a Table Can Be a "Who" (Yes, Really)