David and Janet Hooper left the Fairfax County Animal Shelter yesterday morning as quickly as they came in. But they were shaken, teary-eyed and minus their two aged, leukemic cats.

It was a trip the Centreville couple dreaded but one they decided they had to make. The Hoopers asked the shelter staff to end the lives of Bert and B.D., which stands for Bodacious. One cat was "down to the bones with cancer," both were too weak to eat, David Hooper said.

"Oh geez, don't look back," Hooper, a 33-year-old musician, told his gulping wife as they left the shelter, struggling with 13 years of memories of the cats, one a tabby and the other black and white.

"We're trying to be optimistic," said Janet Hooper, an obstetrics nurse at Fairfax Hospital. "When you think about it, we had a lot of years, but it's hard. It's like if somebody loses a baby. You have to grieve for what you've lost."

So began a day at the busy Fairfax animal shelter, which, like dozens of others throughout the Washington area, serves as a clearinghouse for human emotions as well as homeless dogs, cats, geese, raccoons and more exotic species, including an occasional alligator or kinkajou, a cousin to the wolverine.

The staff and volunteers at the shelter are kept busy answering the phones -- which seem to ring constantly -- caring for animals, soothing owners who come to leave a pet and sharing in the joy of those who arrive empty-handed and leave with an addition to their family.

"I think I use a little more common sense when it comes to animals than regular people," said Lillie Phillips, a clerk at the shelter, who owns a 3 1/2-foot-long python, a talking parrot, a dog and a cat.

Often people who leave an animal are distraught, she said. "I don't pull any punches with them. I'm very comforting and to the point."

After a pause, Phillips added: "Maybe it's something I've been eating, but I've been breaking down lately. You get attached."

According to workers at the Fairfax and Arlington County animal shelters, about 25 percent of the domestic animals they see eventually are adopted. The rest are reclaimed by their owners or are euthanized with injections of sodium pentothal.

Last month, the Fairfax shelter took in 292 stray dogs and 137 cats, and found homes for 129 dogs and 146 cats, officials said.

"We have files full of cats," said Helen Allen, a supervisor at the West Ox Road shelter. "It's very hard to match them." But when they do, shelter workers say, few things are more satisfying.

At the Animal Welfare League Shelter in Arlington yesterday, where soothing music is piped into rooms filled with cages and donated blankets and toys for the animals, Elliott Diamond and his wife, Maria, came across a year-old dog named Wicca.

The Diamonds, who live in Reston, were looking for a companion for their Doberman. They said they would bring their dog in for a compatibility test with Wicca.

"We definitely want it," Diamond, an electronics engineer, said of the mixed-breed dog. "It's up to our dog now."

Saturdays are some of the busiest times at the shelters, as families come to look for new pets and staff members field numerous phone calls.

One caller to the Arlington shelter, located on Arlington Mill Drive, wanted to know if there was a dog that answered to the name of Rambo. A boy called to ask if the staff had seen his dog, which he described as black and green.

At the Fairfax shelter yesterday, Duncan Redditt, a member of the Mid Atlantic Shar-Pei Club, completed a rescue mission. Redditt, of Alexandria, drove off with two of the wrinkled dogs, which he said will go to homes of people who understand them.

Susan Roos of Oakton, who also stopped by the Fairfax shelter yesterday, said she adopted a white goose last year, but the goose, which she named Isabella, disappeared last fall when she was trying to return it to the shelter.

"It started following kids to the school bus stop," she said. "I was afraid it might scare some of the kids."

But on the day she decided to catch the goose and return it, it ran from her, Roos said. While she went for help, Isabella vanished.

In Isabella's memory, Roos donated a 25-pound bag of Purina Duck Chow to the shelter.