How Pets Were Domesticated - A short explainer. A great place to start.
Pets in America - This is a link to the introduction to this book, which contains a great summary of pet-keeping in the United States. A great next step for background reading.
The Fashion Explanation for Pet-keeping - A scholarly paper that does a great job laying out the possible evolutionary reasons people keep pets, then offers its own explanation: it's about fashion!
History and Ethics of Keeping Pets: Comparison with Farm Animals - an excellent scholarly (but not too dense!) paper that questions our ethical relationship to pets by comparing it to our ethical relationship with farm animals
The Invention of Pets - A simple explainer with links to more in-depth resources to take your further in your research
Pets in Colonial America - A fascinating article. You can listen to it in English or Spanish if you prefer!
A video that answers the question: Why Do People Have Pets?
Messengers to the Gods - A great explainer of the Egyptian relationship to animals and the afterlife