20-year-old panda gives birth to new cub at San Diego Zoo

Bai Yun gave birth to her sixth cub at the San Diego Zoo on July 28, 2012.

(CBS/AP) SAN DIEGO - San Diego Zoo has welcomed a record-breaking sixth panda cub.

Officials say the birth of 20-year-old Bai Yun's latest offspring gives the zoo the most births at a breeding facility outside of China.

Bai Yun has birthed all the cubs born in captivity at the San Diego Zoo, CBS News affiliate KFMB in San Diego reported. The new mother almost broke another record. She was a few days shy of being the oldest panda known to give birth.

Zookeepers and researchers watched the birth Sunday afternoon via a closed circuit camera mounted inside the birthing den. Zoo officials told KFMB that they didn't know the panda was expecting until late in her pregnancy because of her age. They expect this will be her last cub, but acknowledge that it is up to her.

In a blog post, zoo officials say Bai Yun immediately scooped the cub into her arms and comforted the newborn.

Because of Bai Yun's advanced age the pregnancy was considered high risk, but zookeepers say mother and baby are doing fine.

Zoo officials won't know the sex of the cub until they examine it in several months. It won't develop its black and white markings for a few months either.

KFMB reported that the cub will be named on its 100th day, according to tradition. Zoo visitors will be allowed to vote for the name.

It will be a while before Bai Yun and the new cub are on display but the public can glimpse them on the Panda Cam at the zoo's website. The new mothers and cub are bonding, and visitors can expect to see them in the exhibit around December 2012, according to KFMB.