If you own a dog, you've heard this rule: 1 year for Fido equals 7 years for you. Turns out, the math isn't that simple. Dogs mature more quickly than we do early on. So the first year of your fuzzy friends life is equal to about 15 human years. Size and breed also play a role. Smaller dogs tend to live longer than larger ones, but they may mature more quickly in the first few years of life. A huge pup might age more slowly at first, but be nearing middle age at 5. Tiny and toy breeds don ...