Surprise: Twins! Giant panda gives birth to two cubs in Austria

A giant panda in Austria just welcomed not one but two little bundles of joy.

Yang Yang, who lives in Vienna's Schoenbrunn Zoo, gave birth to twins, the zoo said Tuesday. The two pandas are Yang Yang's fourth and fifth cubs.

The second panda was a surprise. The zoo initially announced that a panda cub was born on Aug. 7, but more than a week later they realized that there were two of them.

The revelation took some time because the birth was observed by camera, and the cubs are tiny: at birth the visible one was just four inches long.

The Associated Press contributed to this report.