Renowned animal behaviorist and veterinarian Sophia Yin, DVM, MS, who lectured and wrote extensively and invented the Treat & Train reward-based training system, died Monday. She was 48.

Dr. Yin hanged herself at her home in Davis, Calif., Yolo County chief deputy coroner Gina M. Moya said.

A brief message about her passing was posted on Yin's website and Facebook page.

"At this time the family and staff has requested privacy as they struggle to handle this sudden and unexpected loss," the statements read in part.

Colleagues such as Marty Becker, DVM, and certified dog and cat behavior consultant Steve Dale eulogized Yin.

"My heart is broken, and I can't even convey the huge loss of this champion for animals to the world," Dr. Becker wrote on Yin's Facebook page.

"She was a superb presenter, extremely generous, her thinking ahead of most of us, downright brilliant," Dale wrote. "Her loss leaves a gaping hole. Each time we treat an animal with a bit more dignity and patience, [we] will honor her."

John Ciribassi, DVM, Dipl. ACVB, the president of the American Veterinary Society of Animal Behavior, announced Yin's passing to his organization "with a heavy heart."

"Sophia brought the idea of compassionate training and communication with our pets to many of us in the field and to the public," Dr. Ciribassi said. "She [was] instrumental in helping to counter those who were espousing aversive, punishment-based training techniques."

Yin was a 1993 graduate of the University of California, Davis, School of Veterinary Medicine. After going into private practice and realizing that some of her patients had behavioral issues rather than medical problems, she returned to UC Davis to earn a master's degree in animal science with an emphasis on animal behavior. She also taught animal behavior courses for five years in the UC Davis animal science department.

Out of that education and clinical experience emerged a prolific writer, speaker, peer educator and consultant. She wrote newspaper columns and served as a behavior expert on television shows such as Animal Planet's "Dogs 101."

Among her written works were the books "How to Behave So Your Dog Behaves" and "Perfect Puppy in 7 Days: How to Start Your Puppy Off Right." Her company, Cattledog Publishing, also produced a book and DVD titled "Low Stress Handling, Restraint and Behavior Modification of Dogs & Cats."

Treat & Train, also known as Manners Minder, is a remote-controlled, positive-reinforcement device originally designed to teach dogs good behavior at the door.

Yin's animal behavior philosophy started with food and consistent rewards as motivators. She criticized the use of inappropriate force or negative reinforcement.

"The animal may do what you want," she said of harsh training methods, "but it's because they're fearful, and they're not happy. And that is not what we want."

Best-intentioned people sometimes lack an understanding of how to approach animals, she told Veterinary Practice News in a 2009 profile.

"If you went to a physical therapist and they just grabbed you and shoved you in a chair, you wouldn't trust them," Yin said. "And yes, that's what we do with dogs and cats all the time."

Yin spent time on the executive board of the American Veterinary Society of Animal Behavior. She also served on the American Association of Feline Practitioners Handling Guidelines Committee and the American Humane Association's Animal Behavior and Training Advisory Committee.