There are dog smarts, and then there are people smarts.

They have 220 million olfactory receptors. We have 5 million.

They hear 35,000 vibrations per second. We pick up about half of that.

Essentially, they can smell the garbage truck before they hear it. And they hear it before it rumbles us out of our sleep.

They have the better short-range vision. Dogs do. We see farther.

I've seen my dog's future in an MRI. And people smarts indicate this is Dylan's last Christmas with us.

In August our otherwise healthy 13-year-old Welsh corgi was diagnosed with a neurological disease. Degenerative myelopathy is a poorly understood and probably genetic disorder that strikes older dogs, particularly German shepherds, boxers and corgis.

In the four months since the diagnosis, Dylan has lost use of his right rear leg. His left rear leg is fading. His hind quarters have caved in on themselves. Mostly he uses shoulder strength to get around.

As the disease progresses, it takes out everything — his mobility, his breath and his doggy dignity.

But it was not his dignity that delighted us on that January day in 1995 when we picked him from a litter bred in the Antelope Valley.

Ten-week-old Dylan was flinging his stocky self at a frenetic Bumble Ball, a motorized orb designed to bounce noisily off of any flat surface.

Dylan came with a pedigree. But we think he's a mutt, descended from foxes, German shepherds and satellite dishes. There is no other explanation for those ears.

After he flunked out of dog obedience and failed the aptitude test for sheep-herding school, I asked our vet if dogs have ADD. Dylan's just happy-go-lucky, he replied.

Then four years later, when Dylan developed irritable bowel, the vet asked me if he had stress in his life. Not unless he is day-trading while I'm at work, I replied.

Dylan got ulcers and gave them. Regulars at the Thousand Oaks dog park may remember when he reigned like Napoleon over the big-dog side.

Although he met the weight limit for admission to the small-dog area, he played too rough with those butterfly-boned toy breeds. So one day I opened the fence between the two sides, and Dylan never looked back.

I thought it would be his Waterloo when he confronted the biggest dog there. He snarled and trash talked until the big white dog backed off.

After that, he was never challenged.

This was the same Dylan who wimped out and refused to sit on Santa's lap at the pet store.

He has climbed a mountain in the Sierras, hiked the floor of Sycamore Canyon and driven our pickup. At least, he thought he was in charge when my husband put him on his lap and placed his paws on the steering wheel.

To feel in control, I search the Internet for information on Dylan's disease. There I came across a site that demonstrates how to turn totally paralyzed dogs to prevent pressure sores. It broke my heart to imagine Dylan that way.

Dr. Joan Coates, a veterinary researcher at the University of Missouri and an expert on degenerative myelopathy, gives Dylan three to five more months, based on my description over the phone.

How will I know the right time to end Dylan's life? I asked her.

Many owners put them down when they are incontinent and too disabled to get out of their own messes, she explained.

Dylan, the alpha dog, surely would be humiliated to be discovered in that state by his pack.

Meanwhile, he lives life on his terms. He insists on navigating a steep slope that drops to our back fence. He fishtails down and then painstakingly pulls himself up. But what else can he do? There are rabbits there that must be barked at.

He keeps up with current events. With my mom supporting his hips with a long, green scarf, he checks out our mailbox, a kind of canine message board the neighborhood dogs blog all over.

As crippled as he is, he's not supposed to be able to run. But somehow he defies the laws of physics and anatomy as he gallops down the hallway toward the sound of popcorn in the microwave.

Our little Mark Spitz dog paddles in our spa as my husband's arms keep him buoyant.

And I don't know what this says about prospects for world peace, but hating our youngest dog Tyler has given Dylan another reason to live.

A survey released last week showed pet ownership is soaring in this country as is the amount we spend on them. We can dress them in sweaters, feed them venison and call them our fur children, but the truth is dogs and people are different. They have smarter noses. They have keener ears. And in some cases better instincts.

While I worry too often these days about what I will have to do, Dylan focuses on the things he can do.

Applying dog smarts to my people brain, I realize what every loved dog knows. And that is each day and every moment in that day is a gift to savor. And you never know when the next hotdog will fall off the table.

When his eyes tell me the time is right, my gift to him will be to let him go with dignity, grateful for his courage, his trust and, most of all, for his unapologetic Dylan-osity.

— E-mail this Star columnist at ccason@venturacountystar.com.