For years, whenever someone asked how old my Lab Cooper was, I did the math in my head. Six years old? Times seven. Forty-two. Easy. I said it with confidence, like I knew what I was talking about. I did not know what I was talking about.
Then one night — I think it was around 11pm, maybe 10:30? I am bad at remembering exact times — I stumbled across a paper from UC San Diego about DNA methylation in dogs. I did not even know what DNA methylation was. I had to Google it. It took me down a rabbit hole that ended around 3am with me staring at my laptop thinking: I have been wrong about my dog's age for six years.
Actually, it might have been 2am. Or 4am. I just know it was dark outside and I had way too much coffee. Cooper was asleep on the couch. He did not care about my existential crisis.
The times-7 rule is not just slightly off. It is wildly off. A one-year-old dog is not a seven-year-old kid. A one-year-old dog is sexually mature, has adult teeth, and the physical development of roughly a 15-year-old human. Meanwhile a seven-year-old human is still losing baby teeth and believing in the tooth fairy. Not even close.
And the other end is just as bad. A 15-year-old Chihuahua is basically a healthy senior who still wants to play fetch. A 15-year-old Great Dane? That dog has been gone for years. The math falls apart at both ends.
So I stopped saying "times seven." I started saying "it is complicated, but roughly..." and then I would pull out my phone and show them the calculator. Most people do not care about the science. They just want a number. But I care about the science now, and I cannot un-know what I learned.
Here is the thing: I felt like an idiot for believing the times-7 rule for so long. But then I realized — everyone believes it. It is one of those things that got repeated so many times it became "common knowledge." Like drinking eight glasses of water a day, or that goldfish have three-second memories. All nonsense, but we all heard them somewhere and never questioned them.
My vet actually laughed when I told him I used to do times-7. "Most people do," he said. "That is why we have to keep explaining it." He told me about a client who brought in a 10-year-old small dog and was shocked when the vet called it "senior." "But that is only 70!" she said. The vet had to explain that, no, it is actually closer to 56, and yes, 10 is senior for a small dog, and no, the times-7 rule is not real.
I built DogAgeTool because I needed a calculator that actually used the research I found. Something I could send to people instead of trying to explain logarithmic curves at parties. (Pro tip: do not try to explain logarithmic curves at parties. People stop inviting you.)
Now when someone asks how old Cooper is, I say: "He is 8, which is about 55 in human years." And then I watch their face change from "oh, middle-aged" to "wait, really?" And then I get to tell them about the UC San Diego study, and the size-lifespan paradox, and how large dogs age faster because of IGF-1 and oxidative stress. And then they usually change the subject. But at least I am not spreading bad information anymore.
Cooper is fine, by the way. He is 8 now. Acts like he is 5. The calculator says 62, but honestly he seems younger than me most days. I should probably exercise more. I say that every year and then I do not. Maybe this year. Probably not.
Anyway, if you are still using times-7, stop. Just stop. Your dog will thank you. Or they will not, because dogs do not understand math. But you will thank yourself.