The lifespan of pets varies significantly depending on the species and breed. For example, small dogs like Chihuahuas often live 12 to 20 years, while larger breeds like Great Danes typically have shorter lifespans of 7 to 10 years. Cats generally live between 12 to 15 years, but some can reach their 20s with proper care. Factors influencing pet lifespan include genetics, diet, exercise, and healthcare. Regular veterinary check-ups can help detect health issues early, improving a pet's quality of life. Additionally, providing a balanced diet and adequate physical activity can contribute to a longer, healthier life for pets.