Panda cub Xiao Liwu was eager to play with a plastic ball during an exam last month. He made his public debut at the San Diego Zoo on Thursday. Ken Bohn/San Diego Zoo/AP hide caption toggle caption Ken Bohn/San Diego Zoo/AP The Two-Way Agreed, Baby Pandas Are Cute. But Why? January 10, 2013 Xiao Liwu made his debut at the San Diego Zoo. As fans crowded around, hoping to catch a glimpse of the giant panda cub, we asked the question that perhaps needs no asking. Scientists offer clues.