OAKLAND, Calif. _ A California family got the best _ and most belated _ Christmas present this year, one that has really put them in the mood to ring in the new year.

Ann and Craig Magnussen and their two teenage daughters were reunited two days before Christmas with a Chihuahua they lost five years ago. The dog named Taz showed up in the parking lot of the Berkeley Bowl supermarket in Berkeley, Calif., on Dec. 23, a bit dirty and disheveled.

A produce clerk asked longtime customers Dan and Katy McMullan, who have a Chihuahua of their own, to look after the dog. Within hours, the couple took him to the Berkeley Animal Care Services, where a microchip scan revealed his true owners and their phone number.

"My heart was beating so fast _ I couldn't believe it was happening," Ann Magnussen said, remembering the call she received from the animal shelter. "This is the absolutely the craziest thing I ever heard."

Magnussen called her daughters, who were just 11 and 13 when Taz went missing on Dec. 1, 2006.

"They just started screaming, they were so happy," she said.

She said husband Craig got in the car so fast to head to Berkeley, he forgot his wallet. Hours later, Taz was back at home with the family's two other Chihuahuas, Tyson, 11, and the most recent addition to the family, Zoey, 2.

"We're a Chihuahua factory over here," she said.

Magnussen, who declined to say what city her family lives in for fear someone may try to take the dog, said Taz responds to his name when called, even though he's been gone longer than he was with them. Taz was just 2 when he and Tyson got out of the yard of a home the family was renting while building a new house.

The family canvassed the neighborhood looking for the two runaways, finding only Tyson. They put up posters and visited shelters and schools before eventually giving up hope. Just earlier this year, Ann Magnussen threw away Taz's identification papers because she assumed he was dead.

The owners may never know what happened to Taz or how many people have encountered him since 2006. Whether he was stolen or just taken by a good-natured passer-by who didn't know to check for a microchip remains a mystery.

"He was fed well, a little bit dirty but had no fleas," Magnussen said. "I try to give them the benefit of the doubt."

She's thrilled the McMullan family knew the right thing to do. After the produce clerk asked the couple to keep Taz in case an owner came looking for him, the couple decided to take him to the shelter.

"What was really touching is, he had this really ingratiating smile," Dan McMullan said of Taz. "He was the sweetest little dog."

Taz even got along with the McMullans' own Chihuahua, Clarence, who is named for the angel in the Christmas movie "It's a Wonderful Life."

Marcie Burrell, a city animal control officer, said reunions after so many years are rare, maybe two or three per year. She is happy Taz was microchipped, in good health and had a good home to go back to.

"It was cool, of course," Burrell said. "One of the good stories."