When the late New York billionaire Leona Helmsley left $12 million to her white Maltese dog named Trouble, a lot of people were shocked.

But maybe a lot of people weren't.

Americans are pampering their pets more than ever. They treat dogs and cats as if they were human, buying them bathing suits, strollers, antidepressants, and for the neutering-conflicted, testicular implants.

This is more than puppy love. Elena Rodriguez witnessed it when a customer at the Pet-Smart PetsHotel she manages in Glendora, Calif., asked that someone perform the sign of the cross over Sweet Pea, a Shar-Pei and chow mix, every night. One evening, Rodriguez neglected to administer the ritual.

"I was on my way driving home and I'm like, 'Oh, my gosh, I forgot to bless the dog,' " Rodriguez said. She called a co-worker to attend to Sweet Pea.

For people who check their darlings into PetsHotel, she said, "It's not just about watching them overnight."

The link between pet and person has become deep and complex. Humans are relying more and more on pets for comfort as traditional support systems falter, say the experts in relations between the species, with families becoming fragmented, baby boomers facing empty nests, job security a fading notion, employers less generous and, for many, religion under scrutiny.

"There's an extraordinary, revolutionary shift in the relationships between people and companion animals," said Jon Katz, the author of six books about dogs. "People in extraordinary numbers are turning to companion animals, especially cats and dogs, to fill the holes in their lives."

At the same time, people have more money than ever to spend, and businesses are giving them more ways than ever to spend it. Pet industry sales are expected to swell to almost $41 billion in the U.S. in 2007, making it the second-fastest growing retail category, after electronics.

Even Bob Vetere, president of the American Pet Products Manufacturers Association, has been taken aback by the offerings.

"I just got a brochure from a company that makes wigs for dogs," he said. "I don't know when my dog ever walked past a mirror and said, 'Gee, my hair is ugly, I need a wig.' "

Pets have their own bakeries, day-care centers and GPS devices, the latter so their owners can find them faster if they get lost. A Los Angeles-area business called the Best Little Cat House, in Pasadena, is "cage free" and playrooms are outfitted with Web cams so absent owners can observe their kitties.

PetsHotels show appropriately themed movies in its dog suites, such as "101 Dalmatians" and "Lady and the Tramp." (Not "Old Yeller," though. Too tragic.) The chef at Club-Beverly Hills, advertised as "paparazzi-free," whips up kosher food and pasta.

"You have a parallel life now with your dog," said Marjorie Lewis, who owns the club, which is actually in West Hollywood. "If you eat all natural food, you want your dog to eat all natural food."

Petco Animal Supplies Inc. just introduced organic food sections in its stores and is shipping fall fashions, including sweaters and scarves. Also available: a $225 bed that warms or cools to adjust to an animal's temperature.

"We really cater to the pet parent," said Rachel McLennan, a spokeswoman for the San Diego-based company.

Muttropolis, which describes its boutiques as "Crate & Barrel meets Whole Foods for dogs and cats," expects to have 100 stores within five years. Existing stores sell, among other things, all-terrain boots for dogs and soap-free wheat grass shampoo for cats.

Healthcare options have multiplied. Fluffy doesn't have to go to an ordinary vet, she can see specialists — cardiologists, radiologists, neurologists, oncologists, behaviorists. Cats can have kidney transplants at VCA West Los Angeles Animal Hospital.

And dogs that have been spayed can be fitted with prostheses made by Neuticles, a company in Missouri. Owner Greg Miller has found plenty of takers, selling almost a quarter-million worldwide, with California his best market.

"If your dog's leg or tail or nose got cut off, wouldn't he know they're missing?" Miller said. "If you're neuter-hesitant and you want your dog to look like nothing's ever changed, that's where Neuticles come in."

Much of the billions of dollars spent on pets goes for normal stuff, which, these days, includes life-extending surgeries and tooth-and-gum cleansing wipes, but also leashes and kitty litter. People may spend liberally on their animals, but many aren't interested in buying them diamond-studded collars.

"I don't want to de-dog my dog," said Marla Shives, an engineering plumbing specialist from Glendora who named her fluffy white Coton de Tulear "Piper," after, well, pipes.

"I feel personally that when people try to humanize their pets to the point where they put clothes on them, that's about your own needs," she said. "That's not what your dog wants."

In fact, there are serious misgivings about the overindulgence of pets and about the intensity of Americans' feelings for dogs, in particular. It was evident in the scalding reaction to the Michael Vick dog-fighting case, which author Katz found disturbing.

"It resembled the medieval mob. There were just people howling everywhere," he said. "In our culture now, we are loving animals more than people."

That can be a problem for the animals, he said, noting that obesity is a leading cause of death in dogs because their owners can't say no to them.

"The bottom line is, your dogs don't do well when treated like children any more than children do when treated like dogs," he said. "They're different species."

In Covina, Calif., Gloria and Fernando Cervantes, who don't have kids, aren't ashamed to call Dodger, a boxer, "our child."

"We threw her a birthday party on her first year, cake and all," Gloria said. "She had all her friends there. ... We bought them all doggie bones with their names on it."

Fernando described Gloria and Dodger as very affectionate.

"(Gloria's) like, 'Oh, baby, come here.' I think she's talking to me and she's talking to the dog," he said.