The first twin pandas to be born in the United States since 1987 were born today at Zoo Atlanta.

Lun Lun, the giant panda, went into labor Monday afternoon delivering two tiny cubs. The first of the two was born at 6:21 p.m. EDT and the second soon followed at 6:23 p.m. EDT. The cubs are Lun Lun’s first set of twins, and make a total of four offspring born to her.

Lun Lun was impregnated through artificial insemination. The father of the twins is also a 15-year-old giant panda named Ying Yang and lives at Zoo Atlanta, as well. Lun Lun received at ultrasound on June 30, 2013, and it was confirmed that she was pregnant with her fourth cub. However, zookeepers did not see or expect the other cub, making the birth very exciting for everyone involved. Lun Lun remained under 24 hour observation while she stayed in her den, while she was awaiting the birth.

“Twins are an entirely new scenario for Lun Lun, Zoo Atlanta and our animal care teams, who will no doubt be extremely busy over the next few months,” said King. Lun Lun is taking care of one cub while the zookeepers, along with animal management and veterinary teams from Arthur M. Blank Family Foundation Giant Panda Center, care for the other cub in their nursery.

It is believed that giant pandas will only care for one cub when twins are born to them in the wild. This usually leads to death for the twin that is not being taken care of. Therefor, zookeepers are going to rotate out the twins to Lun Lun during there first few months of life.

To follow the twin pandas progress you can view the Zoo Atlanta panda cam at www.zooatlanta.org/pandacam.