I could never quite figure out why otherwise intelligent and thoughtful people would choose to have a dog rather than a cat. Cats don't have to be walked, or taken to the hairdresser to be groomed or to expensive spas to be bathed. They are infinitely more discreet in their sanitary habits. Dogs, as far as I could tell, require almost as much attention as children.

Among those thoughtful and intelligent people who have not figured this out are my brother and his wife. Two weeks ago they called to say that they had arranged all the logistics for a family mission to Florida except for one small matter: their dog. Their dog is a Great Pyrenees. She is no small matter. She is an enormous, shaggy-haired white creature with a massive head and mouth. Shadow, as she is known, had never been kenneled. She is 11 years old and has a limp in her back legs. My brother and his wife had decided they did not want Shadow to be out of sorts while they were undertaking a family mission in Florida, and they had come up with a solution.

Me.

"But what about the cat?" I said.

"Shadow won't bother the cat," my brother assured me, "and the cat won't bother Shadow."

Shadow arrived last week. The gates to the back yard were secured, and she loped around the perimeter. The cat took one look at her and fled across the back deck, under the fence and onto a neighbor's roof.

I left for work. It started to snow, and when I arrived home that evening I discovered that before leaving for Florida my brother had put Shadow in my basement to get her out of the storm. This was fine, except for the fact that it threw Shadow's various schedules completely off. Having slept all afternoon, she wanted to go out at night. She was disoriented and would not eat anything except chocolate chip cookies. My children tried to coax her back inside before they went to bed. She refused to budge from under the deck. It kept getting colder and I continued coaxing. I believe I mentioned she has a very big mouth.

At precisely 12:40 in the morning I was crawling on hands and knees under the deck, lifting her massive head and leading her down the basement steps into the house. She looked utterly miserable. I sat down and started petting her. She sat down and started staring at me. Miserably. It didn't take a dog psychiatrist to figure out she missed her owners. Having no experience with unhappy dogs, I reached into my repertoire for unhappy children. A lullaby came out, and the next thing I knew two giant paws were stretched out on my forearm next to a massive head.

My son the 10-year-old let her out early the next morning, and we got her to eat. A territorial truce with the cat began shaping up. The cat would have the front yard, and Shadow would preside over the back. The cat would have the run of the main part of the house, and Shadow would have the run of the basement. All that was needed to keep the spirit of detente going was a little luck and a lot of closed doors. I wondered how mothers of four coped.

The next day proceeded without incident. At 4:20 the following afternoon I got a call from my son: "Shadow's gotten out," he said desperately. "She got onto Great Falls Street, and Mrs. Newcomb thinks she's been hit by a car."

"Where is Shadow now?"

"We don't know."

"Go find her. I'm on my way."

That particular half-hour drive home was one of the longest I've ever taken. These parallels between dogs and children were getting very close, indeed.

I flew into the house. My husband was there. "It's all right," he said. "Shadow's home. She's asleep."

It turns out that she had managed to push a back gate open and had wandered off. She had walked onto a main thoroughfare in rush hour, and cars had been stopping to avoid hitting her. Our soccer coach's wife saw what was going on and connected the strange dog to a chance remark my son had made two nights before that he was taking care of an older dog. She saw the limp and thought the dog had been hit. One of her children called our house, but in the meantime Shadow had wandered off again. A hunt ensued, and my husband led her home.

He secured the gate, and so far we have had no more crises. Shadow knows her way around and is eating very much better, and she has taken to sunning herself on the deck. We took her for a walk around the neighborhood during the weekend, and she was a tremendous hit with the kids. I discovered what fun it is to walk a dog. And I've discovered what fun it is to have one that is so responsive and gentle and big and just plain lovable.

Maybe those people who love dogs have something after all.