SAN DIEGO — A tiny California mouse now has a big title after winning a Guinness World Record for longevity.

Named "Pat" after legendary actor Sir Patrick Stewart, the Pacific pocket mouse has a gentle personality that endears him to everyone who meets him.

What You Need To Know

  • A Pacific pocket mouse named Pat now has the Guinness World Record for the oldest living mouse in human care

  • Pat is over 9 years old

  • The Pacific pocket mouse is critical to its ecosystem because it disperses seeds of native plants, and its digging encourages plant growth

  • The Pacific pocket mouse is the smallest mouse in North America

Dr. Debra Shier is essentially the godmother of this critically endangered species. As the Brown endowed associate director of recovery ecology at San Diego Zoo Wildlife Alliance, she has established and continues to oversee the Pacific pocket mouse conservation program since 2012. Pat was born in the first year of the breeding program and part of the third litter. He was born at the San Diego Zoo Safari Park on July 14, 2013.

“I was actually the one that mated his parents to produce him,” Shier said.

For years, the smallest mouse in North America was thought to be extinct due to human encroachment and habitat destruction. Now, there are just three tiny populations remaining in Southern California: at Dana Point in Orange County and near Camp Pendleton in San Diego County.

Shier has dedicated her life to making sure they don’t disappear. The Pacific pocket mouse is critical to its ecosystem because it disperses seeds of native plants, and its digging encourages plant growth. Shier estimates they have produced 518 pups and reintroduced 227 into Laguna Coast Wilderness Park to try to establish a new population.

“Everything about them, their morphology, their physiology, is all adapted for the dry environment,” Shier said. “And so pretty much everything they do behaviorally, I find really, really fascinating.”

Pat is now a spotlight on all their hard work over the last decade. In the wild, a Pacific pocket mouse might live a year or two; in captivity, maybe four to six years. Pat is over 9 years old and recently won a Guinness World Record for longevity.

“At an age of 9 years, 180 days, Patrick, male No. 36, is officially the oldest mouse living in captivity,” Michael Empric, an adjudicator with Guinness World Records, said during the ceremony.

“I would like to present this certificate to Debra [Shier] and congratulate the team here. You are officially amazing. Well, Patrick is officially amazing,” Empric added with a laugh.

Empric flies all around the world authenticating world record claims. He noted that while some are goofy and fun, this type of record setting holds a life-saving purpose.

“It’s such a niche for the San Diego community and Southern California,” he said. “You have this endangered species that’s so important for the environment. To see the breeding program here and how successful they’ve been, and then to actually get to meet Pat, he was doing great. It was really fun to get to come out and see that and know that it’s making a difference in the community.”

The world record certificate now hangs over Pat’s habitat, a reminder of how far the Pacific Pocket Mouse has come and the work still to be done.

“It’s been really a labor of love and a Herculean effort to get to this point with this species,” Shier said. “And it’s just amazing to have the recognition for all the work that we’ve done.”

The Pacific pocket mouse weighs about as much as three pennies and gets its name from cheek pouches the animals use to carry food and nesting materials.