ATLANTA (AP) -- Zoo Atlanta officials say a pair of twin newborn cubs a 15-year-old giant panda gave birth to earlier this week are both male.
The twins born to Lun Lun and her partner, Yang Yang, are the first giant panda twins to be born in the U.S. since 1987.
Lun Lun delivered the cubs Monday evening and zoo Atlanta officials have said they were unaware that she was having twins until the second cub was delivered.
Officials were unsure of the cubs' genders until Thursday, and say they're being rotated between their mother and a nursery to ensure they get equal time to bond with Lun Lun.
The cubs have three older brothers: 4-year-old Xi Lan, 2-year-old Po and 6-year-old Mei Lan -- who was sent to China in 2010.