What Dog and Cat Years Really Mean

"How much is that in dog years?" We are used to assuming that for every calendar year, a dog will age the way a human will in seven years. That makes some sort of sense according to a dog's expected life span, but it doesn't tell the whole story. For example, the dog in this picture has one candle on her birthday cake, but she's old enough to have puppies. Veterinary professor Jesse Grady explains the life stages of dogs and cats.

Dogs and cats age differently not just from people but also from each other, based partly on breed characteristics and size. Bigger animals tend to have shorter life spans than smaller ones do. While cats vary little in size, the size and life expectancy of dogs can vary greatly – think a Chihuahua versus a Great Dane.

Human life expectancy has changed over the years. And vets are now able to provide far superior medical care to pets than we could even a decade ago. So now we use a better methodology to define just how old rule of thumb that counted every calendar year as seven “animal years.”

You'll find life stage charts for cats and dogs at The Conversation. According to the cat chart, I have two mature cats and one cat entering his prime.  -via Nag on the Lake

(Image credit: Flickr user Omer Balamir)