On Friday afternoon, a little brown Chihuahua trotted purposefully down an East Oakland residential street - wearing a collar, looking very determined but with no owner in sight.

Animal control officials said the pooch is probably one of the thousands of stray Chihuahuas wandering neighborhoods from San Jose to Vallejo, victims of overbreeding and negligent owners. In fact, stray Chihuahuas comprise the majority of dogs in local shelters and are frequent sights at vacant lots, parks and sidewalks.

"There's such an overabundance of these dogs, what do we do with them all? It's heartbreaking," said Deirdre Strickland, head of a Chihuahua rescue group in Oakland called the Power of Chi. "Especially the tan males. They can be great dogs, but no one wants them."

Popular breed

Chihuahuas have been popular for years, thanks to movies like "Beverly Hills Chihuahua" and celebrities' taste for toting the little dogs in purses. But now they're turning up in huge numbers as strays - either abandoned, escaped or feral.

At the East Bay SPCA, well over half the 3,000 dogs that come in annually are small dogs, and most of those are stray Chihuahuas, said Director Allison Lindquist. In a 24-hour period this week, the facility received five Chihuahua puppies. That's not unusual, she said.

"Eight years ago, there'd be a line out the door of people wanting to adopt little dogs. Not anymore," she said. "Now we have too many of them. It's market saturation."

The numbers are even higher at the city of Oakland shelter. About 75 percent of the 3,500 dogs that arrive at the shelter annually are Chihuahuas or variations thereof, the vast majority stray, officials said.

But "stray" is a loose term, animal officials said. Some of the dogs are truly feral - born on the street and strongly averse to people. Others are escapees or lost, dogs that had a home but somehow got loose. Others have been intentionally abandoned, because the owners moved someplace that doesn't allow dogs, or the dog became too much trouble, or the owner couldn't afford it anymore.

Letting dogs roam

And then there's the last category: dogs that are neither lost nor abandoned, but just run free. Oakland, like most cities, has laws requiring dogs to be on a leash or safely fenced in a yard. But not everyone follows those laws, and in some neighborhoods it's not uncommon for people to just let their dogs roam.

Life on the streets for these pooches is not easy. They're subject to getting hit by cars and attacked by bigger dogs, and can suffer an array of health problems, such as flea infestations, starvation, poisoning and infections. A typical life span for a stray dog is three to five years, animal control officers said.

But one thing they're not is a menace to the public, officials said.

Vickie Bell, who works at the Oakland animal shelter, said that in her time there, "we've never gotten a call about a vicious Chihuahua. So in that sense it's easier for little dogs. You can just pick them up."

Most of the stray Chihuahuas find homes sooner or later, at least those that are reasonably healthy and without major behavior problems. Oakland flies hundreds of them annually to rescue groups in Idaho, Washington and Canada, where Chihuahuas are in demand, gives others to local dog-adoption groups, and sometimes people even stop by the shelter looking to adopt one.

"If they're trained and socialized, they can be great dogs," Strickland said. "But if you don't train them, it can be very hard for everyone."