Stewie was surrounded by family when he succumbed to a yearlong battle with cancer Monday evening at his Reno home, owner Robin Hendrickson said Tuesday. He was 8.
Guinness World Records declared Stewie the record-holder in August 2010, measuring 48.5 inches from the tip of his nose to the tip of his tail.
Hundreds of fans flooded Stewie's Facebook site with memories and condolences Tuesday. The Maine Coon cat was a certified therapy animal that frequently visited a Reno senior center and helped promote animal welfare awareness with the Nevada Humane Society.
"Stewie was always very social and loved meeting new people," Hendrickson said. "He has touched many lives, and for that I am grateful."
Stewie's full name was Mymains Stewart Gilligan. Hendrickson bought him from a breeder in Hermiston, Oregon, in 2005. Last month, he attended the International Cat Show in Portland, Oregon.
"He did really well at the show, even though he wasn't feeling totally perfect," said Stewie's breeder, Valerie Horton, who also serves as the show's entry clerk. "He loved being there because he loved the public. He always did."
Horton said Maine Coons are the largest domestic breed of cats. She's been raising them since 1980.
"It's the luck of the draw," Horton said. "We mostly breed for type and temperament, and then hope for the size. Stewie's father came from some very large cats."
Guinness World Records officials did not immediately respond to inquiries about a successor to Stewie's record. The previous record-holder, Leo, a 48-inch-long Maine Coon owned by Frieda Ireland of Chicago, died several years ago.
Stewie was diagnosed in early 2012 with Lymphosarcoma, a malignant disease of the lymphoid tissues. He responded successfully to chemotherapy and was declared cancer-free, but the remission period was brief, and a vet recently found another, more aggressive tumor on his kidneys, Hendrickson said.
"I knew that although we could fight it, the end was near and so I wanted to simply make him comfortable and let him enjoy the time he did have," she said.