A couple of days ago I took off a couple hours off mid-day to give my son’s math and science class a talk on veterinarianism and animal care. I dragged along a tech, my Sophie and little Tulip, who is no longer so little. (At forty-five pounds, she’s more than doubled her weight since she first came to me six weeks ago.)

The small class of thirteen gifted-program fourth-graders was so full of smart questions on genetics and artificial insemination versus live breeding (really) I could easily have gone on for another hour.

They also asked questions on animal aging and how human years and dog/goat years measured up, astutely noting that my Sophie Sue didn’t look or act the 70 years the standard calculation yields.

You’ve heard the math: seven human years equals one dog year.

Well, that calculus needs some pop-culture debunking for sure. Now that our pets are living longer and we know more about their individual peculiarities we can get to far better guestimates based on size and breed.

Here’s a great set of charts I sent to school with my son yesterday so the kids could play around a little with the math we discussed—while learning something about pets, too, of course.

It’s from School-for-Champions.com, an educational resource website I recommend digging around in just for fun.

On their charts you can observe the difference in ages between humans and animals of several varieties (not just cats and dogs) so we can all consider our own mortality with renewed vigor. Fun!

Why is it kids seem to love this exercise? The rest of us just want to play ostrich when it comes to comparing our six year-old dogs to our forty year-old selves.

What can I say? I spent much of the time in that classroom discussing this—if only by way of avoiding one swift kid’s trick question: “exactly how does the dog sperm get to the dog egg?”