I have contemporaries who describe themselves as “middle-aged.” This fascinates me. Either they have a stupendous ability to deny reality or an utterly unfounded faith in future medical advances. I, for one, do not expect to reach 100 or more years of age.

Our family dogs, however, are already nearly there.

This should be cause for celebration, and in a way it is. It’s amazing. It is also an express ticket to heartbreak.

Until two years ago, I’d never had a dog. This was principally because I like big dogs and I’ve always lived in urban places where owning one would have been unfair to the dog.

Then one day not long ago, I met a woman on the Burton Loop who was walking a large beast: part Siberian husky, part German shepherd, and arguably the most poised and beautiful creature on the Island. I refer, of course, to the dog, although the woman was pretty splendid, too.

This dog will be 14 next month, an age that makes him at least 90 in human years, depending on which doggy age calculator you prefer. But you’d never know it to look at him. This dog is disgracefully robust. He runs like the wind and loves nothing more than to leap over huge driftwood logs on our beach, grabbing “big air.” This, I hasten to add, is despite his having had two major (and very expensive) surgeries in the last 18 months. I hope to be in the same shape at 90 as he is today but, as I already am not, this hope is clearly fanciful.

The woman to whom he belonged and I became a couple. I blame this entirely on the dog. I’d like to say the woman fell head over heels in love with me (as, in fact, I did her) but the truth is I was just the first guy the dog hadn’t snarled at in a long time, so she accepted me, just as he accepted me into his “pack.”

This woman, lately known as my wife, works at an Island veterinary clinic. As a consequence, it was, I suppose, inevitable that sooner or later (it turned out to be sooner) another dog, a “rescue” animal, would join the family.

Thus it was that we gained an aging golden retriever who is also half Afghan hound. Think of her as the fashion model version of golden retrievers: Her Afghan genes make her slender, leggy, long-muzzled and regal but with a golden’s rusty coat and sweet disposition.

Afghans and goldens, as you may know, are two of the goofiest dog breeds on earth. It is an actual fact that we have Afghan hounds in America today thanks to the Marx Brothers — you know, Groucho, Harpo, Zeppo, and the other one, whose name I can never remember (see “more than middle-aged,” above). They’d been on tour in England and stayed at an estate that had Afghans (I refer to the dogs).

In short order, they announced they had to have a pair, as Afghans were the only dogs sillier than they were. Zeppo Marx set up a breeding operation on a farm in Massachusetts. The rest is shaggy, leggy canine history.

Our rescue dog, her golden retriever genes notwithstanding, could easily be an unacknowledged sister of the Marx Brothers.

She is hilariously funny in a slapstick sort of way.

She is way smarter than you’d guess.

And she is dying.

A few months ago, she was bounding along on our beach, leaping and woofing deeply at chimeras, lanky limbs akimbo, and running circles after her tail. All you need to know about this dog is that she chases her tail without ever comprehending that it is a part of her person.

Now she can barely walk. She has spinal cancer. There is a big, square, furless, shaved patch on her back, like a Forest Service clear-cut, where the ultrasound test proved this beyond a doubt. She also has a tumor on her adrenal gland, but the docs say the spinal cancer will get her first. And very soon.

What is it about dogs? How do they manage to survey, map and stake claim to so much of the geography of our hearts? Cats are loving, yes, but they require little of our care, and seem unimpressed when we provide it … except, of course, for food.

Is it a dog’s dependence, its childlike vulnerability, which grips our hearts? Is it its deep intelligence? And in illness, is it that wide-eyed, stoic acceptance of infirmity, that calm and gradual relaxation of ambition, which rakes our hearts like machine gun fire?

An ailing dog will try to be who she remembers she was only weeks ago. And when she comprehends that she can’t be, she accepts it with an equanimity we humans rarely achieve — we who are so determined to assert our immortality; who are so unwilling to accept the depredations, the limitations, the insults of aging; who are so incapable of saying to ourselves, as I suspect a dog does, “Yes, this was good, but my work here is done.”

Three months ago, a vet gave her two to six months. Maybe she didn’t hear him. She soldiers on.

Or maybe she’s holding out for us.

— Will North is a Vashon novelist. His next novel is set on the Island.