So you think you know about dogs?

Sorry, you do not.

I break this news to you only because I got put to such a test Tuesday, along with about two dozen animal-shelter directors, volunteers, dog trainers and others who make a dog-related living.

The task was simple: View 20 dogs on a videotape and identify each one. Is it purebred or mixed? If believed a mix, what is the mixture of each?

How hard could it be?

All I know about dogs, I quickly learned, is that one lives with me. Of the 20 dogs shown, I got the breed correct one time, but only because it looked like Lupe, my mutt.

I did only slightly worse than the professionals.

“I was completely wrong. I probably got three to four out of the 20,” claimed Laurie Buffington, a Berthoud dog trainer, as we left a classroom at the Longmont Humane Society.

“Think you can tell just by looking?” was the teaser for the breed identification study we participated in. It was run by Victoria L. Voith, a professor of animal behavior in the College of Veterinary Medicine at Western University in Pomona, Calif.

What I and the others ultimately learned is you cannot simply look at a dog and know what it is.

Shelter workers, she explained, are generally 75 percent wrong when they list or tell you the breed of a dog. The only sure-fire way of knowing, she said, is DNA testing.

“I started this study,” Voith said, “because I am a lover of German shepherds and was appalled that every short-haired breed with brown hair was called a German shepherd. It simply isn’t so.”

Outside of the Lupe-looking Chihuahua-mix, I thought every dog looked like a pit bull or a shepherd-mix.

“So what in the hell is Lupe?” I jotted in frustration in my notebook about halfway through the session. I was not getting even remotely close.

My favorite of all was the 20th dog, a three-legged cutie that had been thrown from a car. She was not the English sheepdog I suspected, but a shih-tzu. Everyone else misidentified her too.

Through her work, Voith hopes to put to the lie two things: studies on which dogs bite the most, and the wisdom of municipal breed-specific bans, such as Denver’s, where hundreds of suspected pit bulls have been put to death.

“Visual identification simply is not in high agreement with DNA analysis,” she said when I protested that a dog I had falsely, dead-to-rights identified as a pit bull turned out through DNA testing to be mostly Dalmatian. “Dogs in Denver may be dying needlessly,” she said.

She hopes that her work, which she expects to be published in a year, will better inform cities and statistics gatherers on breeds most likely to bite.

“We really don’t know yet. I don’t think we have ever really known,” she said.

The professionals all walked out scratching their heads, each mumbling something akin to “that was very informative!”

“I always thought I was really good at identifying breeds,” a chastened Shantel Southwick, another Berthoud trainer, moaned. “And cities are killing dogs based on uninformed visual identification? That’s pretty scary. It’s heartbreaking, really.”

Bill Johnson writes Mondays, Wednes- days and Fridays. Reach him at 303- 954-2763 or wjohnson@denverpost.com.