Maybe the reason I'm so interested in the past of my dog is because of the dogs of my past.

The first was a collie named Tippy (named for the white tip of his tail). He was a present for my fifth birthday on Long Island, N.Y. Lassie was in its fourth season that year, 1958. Tippy, while he never rescued any children from wells or anything like that, was a wonderful dog. He died prematurely and mysteriously, by poisoning, a few years later.

Accompanying me through puberty was Schatzi (German for "sweetheart"), a high-strung Weimaraner who gave birth to 11 multicolored mystery mutts in my bed in Texas.

In high school, I came home to Otis (named after soul singer Redding), a rambunctious border collie who, after I left for college, would go on to bite at least one visitor and live out his life with the neighbors before our house in North Carolina was razed for an AmeriSuites hotel.

After college, I got my first job in Arizona, and my first dog as an adult - a golden retriever I named Taco, who made being on my own a little less lonely. Later, in Kentucky, came Cuando (Spanish for "when"), whom I found in an abandoned house while working on an article. Then came a dog my boss' family no longer wanted, whom I renamed Carrie (the result of a Sissy Spacek crush). She turned out to be nearly as neurotic as the movie character. Then came Auggie, inherited through marriage.

After Auggie's death, we adopted Hobo (shelter-named), a tall and lanky mutt in California, and later, in Pennsylvania, Fancy (also shelter-named), a smaller version of Hobo.

If there has been a constant in my shallowly rooted life - with its two divorces (not counting my parents'), five employers, 13 changes of state and 22 changes of homes - it is dogs.

Dogs have enabled me to feel anchored, even when I wasn't; popular, even when I wasn't; and maybe a few other things, even when I wasn't.

Finding out more about the past of Ace, my 10th dog, was maybe somehow connected to that - an attempt to provide him some roots in exchange for the rootedness my dogs have provided me. Or maybe it was just selfish curiosity. In either case, the answers I was seeking didn't seem to be coming.

Nearly a month had passed since I sent in his DNA for an analysis that might determine his breeds, and I was still awaiting word on the lab results. Had I flubbed the swab test? Was he so mixed as to defy description? I called to check. The sample was good, and results were expected any day, I was told.

Meanwhile, Jennifer Mead, the Baltimore Animal Rescue and Care Shelter director who was trying to get in touch with the citizen who found Ace on the street and turned him in, was having no luck in tracking him down. Mead had left messages, but no one called back. She said it would be illegal for her to give me that number, or the name or address.

I pestered her to provide a neighborhood, a street name, but she stuck to her guns. The ZIP code of where Ace was found was as far as she would go.

So Ace and I headed there - to 21229. It takes in much of the southwestern corner of the city, the neighborhoods of Violetville and Irvington, St. Agnes and St. Joseph's, Yale Heights, Allendale and many more.

21229 is pretty mixed itself, according to the U.S. Census - 11,000 whites, 37,000 blacks and about 1,000 Asians. Among the 50,000 people living in its 5.8-square-mile area are those of ancestries including German, Irish, Italian, English, Lithuanian, Greek, Dutch, Jamaican, Welsh, Austrian, Czech and Swiss.

It was far too big and populated an area to have much hope of finding someone who remembered Ace, but it was as close as we were going to get, and it gave Ace a chance to return to his homeland - or at least where he was when someone cared enough to take him in and call authorities.

This would be a good time to thank that person. Ace, based on what I've seen, would have had no problem finding food enough to survive life in the wilds of Baltimore, but his traffic safety skills aren't too strong. Likely, that person - whomever he was - saved a life by calling animal control.

Likely, too, had the city animal shelter not have been revamped into the quasi-nonprofit BARCS that year, it would have been Ace's last stop.

Before 2005, as many as 90 percent of the dogs and cats that entered the city animal shelter ended up getting euthanized, Mead said. Today, with a greater emphasis on increasing the number of adoptions and rescues, that figure has dropped to less than 50 percent.

Nationally, between 6 million and 8 million cats and dogs enter shelters each year, and about half of them - most often mutts - are euthanized, said Stephanie Shain, director of outreach for the Humane Society of the United States.

Close to half of American dog owners - 46 percent - own mutts. While American Kennel Club registrations have declined in recent years, purebreds are still the dog of choice, with 61 percent of those who have dogs opting for them, according to a 2005-2006 report by the American Pet Products Manufacturing Association. (The overlap is from those who own both.)

Dogs, scientists believe, originated from a population of wolves that lived in China 15,000 to 40,000 years ago and became domesticated by humans. For centuries, they were bred and chosen for their working skills, such as herding, hunting or guarding.

Gradually, they made the transition from worker to companion. Today, they are chosen more for their looks than anything else, with TV shows and movies playing a big role in determining the next "hot" breed of dog.

Hottest now are "designer dogs," such as the labradoodle and the goldendoodle, originally developed by crossing poodle and retriever.

"These mixed-breed dogs are the latest craze," Shain said. "Everybody wanted a pug, now everybody wants a puggle. Certain dogs rise and fall, and everybody wants to have the latest 'it' dog."

Sometimes, the surge in popularity is followed by a surge of that breed showing up in shelters. But the vast majority of homeless dogs are still mutts like Ace.

Ace and I stopped in three neighborhoods in 21229. We visited a firehouse, talked with some families and traipsed around a park. Ace did a lot of sniffing, but he always does. He made a couple of friends, but no one recognized him.

As we called it a day, I began to realize the only one who might know where Ace came from was not a person at all.

It was Ace.

Too bad dogs can't talk.

Or can they?

john.woestendiek@baltsun.com