World's oldest mouse discovered

The San Diego Zoo Wildlife Alliance announced on February 9 that a tiny California mouse has set a Guinness World Record for longevity at 9 years and 209 days old.

Photo of Pat the mouse provided by the San Diego Zoo Wildlife Alliance. (Photo: San Diego Zoo Wildlife Alliance/AP).

The rat , named Pat after "Star Trek" actor Patrick Stewart , was born at the San Diego Zoo Safari Park on July 14, 2013, as part of a conservation breeding program, AP reported on February 9.

The San Diego Zoo Wildlife Alliance says Pat is a Pacific scrofulous mouse (Perognathus longimembris pacificus) , the smallest mouse in North America. According to the U.S. Fish and Wildlife Service, the mouse typically measures 4 to 6 inches from nose to tail tip and can weigh 2 to 3.5 ounces, according to ABC.

The rat once had a range stretching from Los Angeles to the Tijuana River Valley, but its numbers declined after 1932 due to human encroachment and habitat destruction, the organization added.

The Pacific scrofulous rat was thought to be extinct for 20 years until small, isolated populations were rediscovered in 1994 at Dana Point, USA. But it remains endangered.

In 2012, the San Diego Zoo Wildlife Alliance launched a breeding program to help save the Pacific scrofula from extinction.