At 1 month old, this cub shares several things in common with Tai Shan at the National Zoo in Washington, D.C. They were born within a day of each other in early July. Their parents come from the same place— Mei Xiang and Tian Tian were born in Wolong – so they probably share a few relatives. They seem to grow by the hour. However, the Wolong nursery cub is a twin and as a result, Tai Shan is much larger. Wolong experts have found that singletons always weigh more than twins.