QUEST FOR LONGEVITY Old dogs, new research and the secrets of ageing

JAMES GORMAN

The ways that dogs grow and age may provide potentially useful similarities with people. Dogs go through stages in their life, just as people do, as is obvious to anyone who has watched their stiff-legged, white-muzzled companion rouse themselves to go for one more walk. Poets from Homer to Neruda have taken notice. As have folk singers and storytellers. Now science is taking a turn, in the hope that research on how dogs grow and age will help us understand how humans age. And, like poets before them, scientists are finding parallels between the two.

Their research so far shows that dogs are similar to us in important ways, like how they act during adolescence and old age, and what happens in their DNA as they get older. They may be what scientists call a “model” for human ageing, a species that we can study to learn more about how we age and perhaps how to age better. Most recently, researchers in Vienna have found that dogs’ personalities change over time. They seem to mellow in the same way that most humans do. The most intriguing part of this study is that like people, some dogs are just born old, which is to say, relatively steady and mature, the kind of pup that just seems ready for a Mr. Rogers cardigan. “That’s professor Spot, to you, thank you, and could we be a little neater when we pour kibble into my dish?”

Mind you, the Vienna study dogs were all Border collies, so I’m a little surprised that any of them were mature. That would suggest a certain calm, a willingness to tilt the head and muse that doesn’t seem to fit the breed, with its desperate desire to be constantly chasing sheep, geese, children or Frisbees.

Another recent paper came to the disturbing conclusion that the calculus of seven dog years for every human year isn’t accurate. To calculate dog years, you must now multiply the natural logarithm of a dog’s age in human years by 16 and then add 31. Is that clear? It’s actually not as hard as it sounds, as long as you have a calculator or internet access. For example the natural log of 6 is 1.8, roughly, which, multiplied by 16 is about 29, which, plus 31, is 60. OK, it’s not that easy, even with the internet. To bring the comparisons home, the researchers compared an ageing Labrador retriever to an ageing Tom Hanks. They used a lab because that’s the kind of dog they studied. And they used Tom Hanks, because, well, everybody knows Tom Hanks. For most of us, of course, there is no pleasure in seeing a dog get older, but seeing even a beloved celebrity subject to the irresistible march of time is somehow reassuring. Sometime in the future the A-list may be able to purchase immortality, but not yet.

Scientists also reported recently that adolescent dogs share some of the characteristics of adolescent humans, like, say, “reduced trainability and responsiveness to commands.” Not your children, of course, but those of other parents. However, teenage dogs don’t torment their actual mothers. They complain to their humans. That means a double whammy for some pet owners. If you happen to have adolescent human children as well as adolescent dogs and you all are stuck at home in close proximity because of a worldwide coronavirus pandemic, then all I can say is more research is required.

They involve some groundbreaking work and could have potentially important conclusions. Scientists are unsure about whether the physical decline seen in ageing in dogs and humans, in fact in all mammals, is related to the process of development in earlier life, or whether the decline is a different process altogether. The researchers found that the pattern of methylation suggested that the same genes may be involved in both processes.

Good methods of comparing dog and human ages are important. Dogs are increasingly seen as good models for human ageing because they suffer from it in many of the same ways humans do. As the Dog Ageing Project, which is collecting genetic and other information from a vast number of pet dogs, puts it on its website, the goal of the research is “Longer, healthier lives for all dogs … and their humans.”

James Gorman is a science writer at large.

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