Lending helping paws to a good cause, dogs and owners traversed a five-kilometer route up and down the trail, raising money in a walkathon meant to help the nonprofit Furry Friends with its humanitarian efforts. The organization brings pets to nursing homes, facilities for disabled or seriously ill children, and hospital rehabilitation and psychiatric wards throughout Santa Clara and San Mateo counties.

Although organizers said they are still tallying the books, they are already pleased about the outcome.

Last year, Diamonds in the Ruff raised more than $6,000, said Furry Friends President Sal Guardino. And this year, the event was much bigger.

Event co-chairwoman Joanna Rustin agreed.

"We had about double the number of participants that we had last year," she said, adding that the number of booths and sponsors was also up dramatically from the previous year. "It was a big success."

Furry Friends "unofficially" began in 1979, when Judy Kell, whose daughter had cancer, realized that whenever her cat was around, her depressed child's spirits were lifted, Guardino said.

"She and her veterinarian started the whole thing up," he said. They actually went to local pet stores, borrowed rabbits, dogs and cats and took them to convalescent hospitals to cheer up the patients. By 1983, they incorporated into a nonprofit organization.

Members are all volunteers. And although they have pets ranging from cats to reptiles to miniature horses, about 85 percent of them have dogs, Guardino said.

"And besides," he said, "it's not easy to take a cat on a walkathon."

But walking was only one of many activities of the day. Visitors were treated to a dog-agility demonstration, raffle-ticket giveaways and a doggie ice cream social. But by far the most popular activity was the Best-Dressed-Pet Contest, for which pet owners like Milpitas resident John Carrion dressed up their dogs in elaborate costumes.

Carrion gussied up his dog, Abigail, in a San Jose Sharks jersey. He also added "Nabokov" to her name in honor of the Sharks' goal tender, Evgeni Nabokov.

"I think Abigail 'Nabokov's' chances of winning are very good," Carrion said. "The Sharks are doing well, and so will she."

But he faced stiff competition.

Dogs came dressed as princesses, cowboys, angels and bumblebees. One dog came dressed as a hula dancer; another even came as Elvis.

But the biggest bow-wows went to winners Henry and Chester, a pair of dogs out of Mountain View.

Henry's owner, Cynthia Jimes, dressed him up in a margarita outfit; Chester's owner, Kate Tracy, designed a custom-made taco costume.

"We were brainstorming ideas one day and just came up with the idea of making a taco out of a dog," Tracy said with a laugh. "It's kind of gross even thinking about it."

Although the costume title went to the dogs, Guardino said the biggest winners were the Furry Friends volunteers.

"It was kind of neat that we could have a single day in which we got to be the recipient of our pets' love, instead of facilitating that love to others," he said.