It’s hard to imagine our world without Stuart. That’s ironic because 15 years ago, it wouldn’t have been hard to imagine our world with Stuart.

But he’s getting to the age where you don’t buy dog food in bulk. And it’s time to start thinking about nature’s course – even though there is that nagging hope that somehow he will be the exception to life’s nonnegotiable rule. Neither my husband nor I had a dog growing up. The closest thing to a pet in the home of my fastidious single mother were dust bunnies. I used to name them. My husband grew up in an apartment in the Bronx  so small that his bedroom was a hallway. Not much floor space for a four-legged friend. Also, I could never stop thinking that somewhere deep in the recesses of a dog’s wolf-mind was just the tiniest inclination to run me down in the back yard and drag me off to share with the pack.

Stuart came to us through the single-minded lobbying of a very determined little girl. She said we could never really be a family unless we had a dog. She had us at “family.” I thought we might ease our our way in with a nice little Shih Tzu or maybe a Pomeranian, to which my husband responded: “Might as well just get a hamster.” So we went the other way – yellow lab, all 95 pounds of him. Our Stuart experience went so well that we doubled down with another yellow lab, Polly. When Polly came into our lives, Stuart was starting to slow down from a life that never moved all that fast to begin with. In the drive department, let’s just say that if it was Stuart instead of Lassie, Timmy would still be in the mine shaft.

Polly, by comparison, is a crackling wire. She skidded across the hard wood floor and into our lives, a bundle of brains and kinetic disobedience. Stuart was smitten from the start. No amount of ear-pulling, tail biting or stealth attacks while he was fast asleep could shake his patient affection. He watched, wagging his big yellow tail, as she would gobble down his food. I look at them curled up together in a shaft of afternoon sunlight coming through the back door, I think about Stuart’s hour-glass, and I wonder: what is it about dogs? They careen through our lives knocking things over, chewing things up and creating unpleasant smells, trails of mud and a level of confusion unknown to canine-free environments.

Before I had them, I would watch other dog owners and wonder: who signs on for this? It’s still a good question. I know about the studies that say dogs lower blood pressure. But I doubt any doctor would prescribe beta-blockers and a lap dog. I know about their supposed healing powers. But neither one of ours has had a measurable effect on flu season. I know about their unconditional love. But give them a month in the home of someone else who loves them, and the unconditional love would prove transferable.

My 14-year study of one family suggests something else. I’ve observed us before and after canine arrival. And what I see is the chance to give yourselves fully and without reservation to the care of another creature. Making them feel safe and happy makes us feel safe and happy.

There is some scientific evidence. It’s called biophilia – an oddly scary term for an interesting idea: we are genetically programmed to interact with nature. It’s an instinctive search for connection with other living things. It’s a connection that works quite nicely for dogs.

I have a friend who told me about being propped up in bed, he and his wife watching the weatherman warn of below zero temperatures – and the need to make sure that all pets are safely indoors. He looked down at their 85 pound golden retriever, stretched out in his usual place between them, on his back, snoring, and said “Do you think he’s going to be ok?”

It’s wonderful what dogs do for us. But the best part might be what they let us do for them.