One dog year is not really seven human years. Here is how dogs really age and why size matters.
How do dog years work?
Dog years compare how old a dog's body is to a person's. Puppies grow up incredibly fast in their first year. By its first birthday, a dog is about as grown up as a 15-year-old. Year two adds about nine more, making it like a 24-year-old.
What happens after that?
After that, each dog year counts as only about four or five human years. But big dogs age faster than small ones. This means big dogs grow old sooner and small dogs often live several years longer. So it is not seven years every year, because dogs age fast at first and then slower.
