A year in a dog's age is equal to seven years of human life, right? Well, not exactly. That formula would make my chihuahua fifty-six years old. But she's as spry and lively as a puppy. How is this possible?

It turns out it's not quite that easy to figure. The size of the dog makes a difference. Different breeds mature and grow differently. In general terms, a dog's first year of life gets her to adolescence-  say high school. The second year, she grows to full physical maturity - let's say college - grown, but not exactly mature. From there, it really depends on the breed. An eight-year-old large dog might be considered fifty-five or older in human years, but a tiny one only forty-something.

Here's a chart I found at Pets.WebMD.com.

I think my three pound chihuahua's younger than the charts would indicate, and she definitely acts like a reckless teenager!

Wow, I just realized, in dog years, I'm not even eight yet!