For thousands of years people have kept and cared for domesticated animals, often developing strong emotional ties with their pets and regarding them as members of the family. While once important for the services they provided—including rodent control, hunting, and guarding—pets have become even more popular as companions. Noting that relationships between people seem to be less reliable and more complicated, Veterinarian Aaron Katcher described the appeal of pets, explaining that animals offer "a much less difficult relationship." Pets have made an impact on more than just their owners, however. Stories of pets' heroism, hilarious escapades, and loyal companionship abound throughout popular media.

The dramatic heroism and unbreakable devotion of some animals is reflected in literature. In stories like The Incredible Journey (1961) loyal pets brave the Canadian wilderness to find their families, Wilbur wins the heart of a small farming community in Charlotte's Web (1952), and in...