Phil McCarten, Getty Images Paris Hilton with Tinkerbell at the 2005 Los Angeles Gay Pride Parade in June. Click photo for larger image.

She was here, she was there, she was virtually everywhere. Blond and skinny like her owner and almost-constant companion, a Chihuahua named Tinkerbell was the "it" dog for quite some time.

She was photographed on the arm of Paris Hilton or riding in the designer purses and bags toted by the hotel heiress. Tiny Tink, clad in pink outfits and teeny tennis shoes, was on camera almost as much as Hilton and pal Nicole Richie in the reality television show "The Simple Life."

And then came word that Tinkerbell, a so-called "teacup" Chihuahua, got too big and was dumped by Hilton. Internet sites and blogs, tabloids and even mainstream newspapers reported this month that Hilton had replaced Tinkerbell with a newer, younger, smaller dog named Bambi.

"People want them as a fashion statement, and that's the wrong reason to get a Chihuahua or any other toy breed," said Lynnie Bunten, of San Antonio, Texas, who has owned and loved Chihuahuas for nearly 40 years. She also has bred the dogs and placed them in show competitions for nearly that long.

Because she occasionally has puppies for sale, Bunten should be happy that the demand for Chihuahuas -- the smaller the better -- has skyrocketed, right? Wrong.

"Just last week I turned down a 21-year-old girl" who flunked the interview process imposed on prospective adopters, Bunten said. "She was really mad. She said she could have sent me a lot of customers because all her friends want Chihuahuas as fashion statements."

Though Bunten sells very few puppies, she currently is looking for homes for two adult mixed-breed Chihuahuas that she rescued from a pound. She also has a long list of Chihuahuas all over the country who need new homes because their former owners became unwilling or unable to keep them.

Bunten is president of Chihuahua Rescue and Transport as well as the breed rescue referral representative for the Chihuahua Club of America. She and hundreds of volunteers all over the country provide temporary foster homes for castoffs while finding owners who will provide what rescuers call "forever homes."

Many breeders and all good rescuers screen potential owners and often have to explain why Chihuahuas might be the wrong pets for them.

"We're terrible salesmen," said Bruce Shirky of San Antonio, first vice president of the Chihuahua Club of America.

The club Web site has a separate page titled "Tea Cup Statement." There is no such thing as "teacup" dog, the statement says, and the smaller dogs should not be considered to be "of greater monetary value."

Some breeders charge thousands of dollars for the "teacups." Breeders of other dogs are also advertising "teacups," including toy poodles, Maltese, Pekingese, Pomeranians, Yorkshire terriers, Shih Tzus and Lhasa apsos.

The maximum size of a full-grown Chihuahua is 6 pounds, according to the official breed standard of the American Kennel Club. Teacup fans are looking for dogs that will weigh 1 to 3 pounds.

"The so-called teacups are probably unhealthy runts," said Shirky. "I've been breeding for 30 years. When they are that small, there is almost always something wrong with them" and they generally "won't live more than a couple of years."

Health problems can include hypoglycemia as well as knee problems, which can often be fixed with surgery that can cost $250 to $2,000.

Paris Hilton isn't the only culprit here. Other celebrities own toy breeds, and undoubtedly some are good owners.

But Chihuahuas are virtually poster-dogs for the "teacup" and "wearable dog" trends.

"The Taco Bell Chihuahua was around for a long time," and that spurred sales. "We actually got a call from a lady complaining that the Chihuahua she bought wasn't talking," Bunten said.

A Chihuahua also appeared in the film "Legally Blonde" as an accessory for fashionista Reese Witherspoon, and the breed has been photographed with Madonna, Jennifer Lopez and Paula Abdul.

Celebrities' fascination with small breeds goes back to at least the 1950s, when band leader Xavier Cugat often performed with a tiny Chihuahua in his pocket, Bunten said.

"He was a breeder," she said. "Those were always young puppies. They did not stay that small."

Contrary to what we see in TV commercials and on the red carpet, ultra-small dogs are not really go-everywhere pets.

"They get tired. They get sensory overload. They can get dehydrated. A lot of Chihuahuas don't like strangers. Personally, I don't think Tinkerbell looks happy in the pictures I've seen. Tinkerbell looks stressed," Bunten said.

If you see a Chihuahua shaking and shivering, that's not normal.

"They are cold or stressed or in pain," she said. "My Chihuahuas do not shake."

As for Tinkerbell's outfits on "The Simple Life," Bunten didn't think she was pretty in pink.

"That is NOT her color," Bunten said.

Some dogs need clothes.

"Up there in Pennsylvania, if it's too cold for you to go outside naked, it's too cold for a Chihuahua to go outside without a coat or sweater," she said.

While carefully avoiding the mention of any celebrity's name, the American Kennel Club has issued statements urging prospective pet buyers to do research to find a breed that will fit the needs and the lifestyle of their families.

Breeds that weigh less than 20 pounds have been rising in popularity in recent years, according to another AKC news release in April.

Since 2000, the AKC's Top 10 list of dogs, based on registration figures, has included the Yorkshire terrier, Shih Tzu, Chihuahua and dachshunds, the smallest breed in the hound group.

The AKC registered 24,850 Chihuahuas in 2004, when they were No. 10. As a basis of comparison, there were 146,692 registrations for Labrador retrievers, which have held the No. 1 spot for more than a decade, and 52,550 for the No. 2 golden retriever.

Less well-known small breeds are showing big percentage increases, according to the AKC. Since 1994, French bulldog registrations have increased 252 percent; Brussels griffon, 234 percent; Chinese crested, 134 percent; and the papillon, 122 percent.

Dogs in the toy group were developed to be companions, "which means they don't do well if left alone for long periods of time," said Lisa Peterson, AKC's director of club communications. They need less exercise than big dogs, but they do need exercise.

Toy breeds take up less room in the family car, and they are perceived as good pets for apartment and condo dwellers. But that's not always the case.

"Do you hear my Chihuahuas barking in the background?" Bunten asked, during the telephone interview. "They do that a lot. Chihuahuas are very territorial" and bark a lot when they see or hear things, including delivery persons. That's makes them good watchdogs but potentially unpopular neighbors in thin-walled apartment buildings.

"A lot of people want small dogs because they have children," Bunten said, but toy breeds generally cannot withstand the vigorous play and the rough-and-tumble of multiple toddlers and 10-and-younger children.

And here's another sobering fact, noted on many breed Web sites and by the AKC : Small breeds have a well-earned reputation for being difficult to house-break.

There are many ways to start your research. The AKC Web site -- www.akc.org -- has information on more than 150 breeds, including links to the Web sites of breed clubs and rescue organizations. Among those is www.chihuahuaclubofamerica.com, which has biographies of rescued Chihuahuas that need new homes.

Tinkerbell is not on that site. She reportedly has been taken in by Kathy Hilton, Paris' mom.