12/07/2011 AT 8:00 AM ET
The world’s oldest dog, a mixed-breed named Pusuke, died on Monday at 26 years old.
Born in 1985, Pusuke had lived with owner Yumiko Shinohara in the Tochigi prefecture of Japan, and had been officially recognized by the Guinness Book of World Records for being the world’s oldest dog since last December.
“I’m so sad,” Shinohara told the Shimotsuke Shimbun newspaper, according to Sky News. “I would like to tell him that I appreciate he lived a long, healthy life.”
Until the day of his death, Pusuke had maintained a healthy lifestyle, eating well and getting twice-daily walks. Shinohara believes the dog died of natural causes.
[RELATED_TEXT “Can’t get enough pet news? See more on PEOPLE Pets