The world’s oldest mouse? Meet Pat, who now has a place in the Guinness World Records

A woman and a man stand near a lectern between two large photos of a mouse
Debra Shier, left, associate director of Recovery Ecology at San Diego Zoo Wildlife Alliance, receives a plaque from Michael Empric of Guinness World Records during an event that recognized Pat, a mouse in the park, as the oldest mouse in the world.
(Ana Ramirez / San Diego Union-Tribune)

It’s official. The world’s oldest mouse in human care is a tiny critter living at the San Diego Zoo Safari Park.

Guinness World Records adjudicator Michael Empric came from New York to the Escondido park Wednesday to bestow the title on Pat, a Pacific pocket mouse born at the park nine years and 210 days ago. The species is endangered, and Pat is part of a breeding program that has introduced some mice back into the wild.

The recognition is a first for the Zoo and Safari Park, which has earned worldwide acclaim for many things, but has never had an animal that was the oldest on record.


It also was a first for Guinness World Records, which previously had no category for world’s oldest mouse.

“There may be old mice, but they don’t have birth certificates,” Empric said at the ceremony held at Beckman Center for Conservation Research at Safari Park. “So what we needed was documentation.”

Empric said the San Diego Zoo Wildlife Alliance supplied all appropriate records, and on Wednesday he personally checked on Pat, who is not on public display.

“He is alive and kicking,” he said. “He is doing really well. He was in a great mood, eating some buckwheat, taking some pictures. He was in tip-top shape, so I was very excited to see that.”

Pat is named after actor Patrick Stewart, best known for playing Capt. Jean-Luc Picard on “Star Trek.” He’s not the only mouse with a celebrity name, as his mother was named Betty White.

While the recognition is a novelty, it helps bring attention to the endangered Pacific pocket mouse and a conservation program that is repopulating the species in Southern California, said Debra Shier, associate director of Recovery Ecology at San Diego Zoo Wildlife Alliance.


“It’s really exciting for the attention to the program, and I think it also says a lot about the San Diego Zoo Wildlife Alliance’s commitment to care of these animals,” she said.

Close-up of a Pacific pocket mouse
Pat, a Pacific pocket mouse at San Diego Zoo Safari Park, is 9 years old, making him the oldest living mouse in human care.
(Ken Bohn / San Diego Zoo Wildlife Alliance)
Close-up of a Pacific pocket mouse
Pat, a Pacific pocket mouse at Safari Park, is in the Guinness World Records.
(Ken Bohn / San Diego Zoo Wildlife Alliance)

Pat was born July 14, 2013, and was in the third litter born in the Pacific pocket mouse conservation program, which was established by Shier the previous year. The Pacific pocket mouse is the smallest mouse species in North America, ranging in size from four to six inches from nose to tip of tail and weighing slightly more than a quarter. Pat, who is small even for a pocket mouse, is one of 165 mice in the program.

The Pacific pocket mouse’s range once stretched from Los Angeles to the Tijuana River Valley, but the species has been in decline because of human encroachment and habitat degradation. They were believed to be extinct for 20 years until a small population was discovered in 1994 in Dana Point.

Shier said about 500 mice have been born in the conservation program, and about half have been released into a new population in the Laguna Park Wilderness Park, which was established in 2016 with support from Orange County Park, the U.S. Fish and Wildlife Service and the California Department of Fish and Wildlife.


Three other small populations also are known in Southern California, and Shier said a fifth population will be established next year.

The idea of seeking a world-record recognition for Pat came about on a whim, she recalled.

One day while documenting the death of one of the mice in the park’s captive breeding facility, somebody asked if it was the oldest mouse in the program.

“I said, ‘No, he’s only like 8. We have an older mouse,’” she recalled. “That got me thinking I should go look at the data base and see how old he is. And when I did, it turned out he was over 9 years old, which sort of stunned me.”

She searched online for information about the longevity of mice and found the oldest one on record was 7 and a half.

“I reached out to our PR team and said, ‘Hey, I have this sort of crazy idea, what do you think?’” she said.

 A life-size cutout of Pat the pocket mouse sits on the palm of a hand to show his tiny size.
A life-size cutout of Pat the pocket mouse sits on the palm of a hand to show his tiny size.
(Ana Ramirez/The San Diego Union-Tribune)

The conservation breeding program saw the birth of 31 litters last year for a total of 117 Pacific pocket mice pups, a new record. Many of the mice will be reintroduced into the native habitat this spring.

While this is the first record for an animal at Safari Park, the San Diego Zoo does have one world record to brag about. For the zoo’s centennial in 2016, it was recognized by Guinness World Records when about 500 participants set the record for most people performing with hand puppets.

Empric, who has worked for Guinness World Records for 11 years and travels throughout the United States and Canada as an adjudicator, said he was last in San Diego a few years ago when he visited Petco Park to document when a dentist tried to set a record for most people flossing. The attempt fell short.