Sullivan is a 15-year-old Sunnyvale resident with curly brown hair and a charming smile. She doesn't look intimidating, but for the past year she has been a source of headaches for some pet shops that sell chinchillas.

As a chinchilla lover, she has threatened to sue pet shops for failing to improve the living conditions of the chinchillas they keep for sale.

"They keep chinchillas in aquarium-like containers," says Sullivan, a sophomore at Archbishop Mitty High School. "Chinchillas are not fish. They need a big cage so they can jump around. And chinchillas are nocturnal animals. They need to live in a quiet place."

Chinchillas, a type of rodent originally from South America, have become one of the most popular pets because of their cute appearance. They have inquisitive round eyes and a curled tail. They look like a combination of a guinea pig, a rabbit and a squirrel and they live from 12 to 20 years.

Despite chinchillas' increasing popularity, few people know how to properly take care of them. As a result, many chinchillas end up dying before their time or being abandoned. More people are deserting their chinchillas or giving them to animal shelter organizations such as the Humane Society of Santa Clara Valley or the California Chinchilla Association.

In 2002, the California Chinchilla Association, a Menlo Park­based nonprofit organization that rescues and provides education on chinchillas, has conducted more than 50 rescues.

Believing that education is the best way to help owners and their chinchillas, Sullivan has worked with the California Chinchilla Association to provide chinchilla education at local pet shops.

"It's very important for people to understand the responsibilities that go into keeping a pet," says Sullivan, who has a horse, two cats, two dogs and four chinchillas. "Chinchillas aren't hard to take care of. But people must keep in mind they aren't easy, either."

She adds that owners should give chinchillas fresh food, water and hay every day. They should keep their temperature between 65 and 80 degrees Fahrenheit to prevent a heat stroke. Chinchillas also need to have a dust bath at least once a week to maintain healthy fur.

Sullivan says she became interested in chinchillas when she was 10 years old.

"I watched a program on Animal Planet about chinchillas," Sullivan says. "I thought they were so cool. I went on my computer and did research. But I didn't decide to have one until I had researched for almost three years."

Her research brought her to the California Chinchilla Association.

Sullivan met the association's founder and president, Lani Ritchey, and bought a chinchilla named "Nut" in May 2002.

"People abandon their chinchillas for various reasons," says Ritchey, who keeps about 12 rescued chinchillas in her living room and bedroom while they await adoption. "Some people are laid off and return to their native countries. Some give their chinchillas to rescue when a relationship ends or a baby is born. Some simply don't know how to take care of chinchillas. Whatever their reasons may be, the poor pets are always the first ones to suffer if something goes wrong with their owners' life."

Ritchey says it takes time and love for rescued animals to regain trust in human beings. One of the rescued chinchillas had to go through massage therapy before it would allow others to touch it again.

Ritchey has been careful in selecting foster families for her rescued chinchillas. She first lets prospective owners play with all the rescued chinchillas to see whether they know how to handle chinchillas and whether the chinchillas like them. She also relies on her golden retrievers and most people-friendly chinchilla, "Nero," to test future owners.

"Animal people have the right body language," Ritchey says. "They know how to pat an animal, move around an animal." Michelle has no problems at all."

To help new owners, Ritchey calls them every week in the first month.

"I always tell people they get a chinchilla mother-in-law," Ritchey explains.

Most owners send pictures of their chinchillas to Ritchey. They also visit Ritchey when they want to breed their chinchillas.

Sullivan got "Chica," one of the association's rescued chinchillas, for Nut in July of 2002. Chica gave birth to two baby chinchillas on Nov. 17, 2002. Sullivan will give the two baby chinchillas to one of her best friends, who she believes will be a responsible owner.

"Chinchillas are not for everybody," Sullivan says. "It takes a mature person to take care of them."

For more information about the California Chinchilla Association, visit www.cachins.org.