The National Zoo’s Giant Panda female, Mei Xiang, gave birth to a cub Friday, the zoo announced. Then, on Saturday evening, after a brief scare that the cub had died, zookeepers learned that a second cub had been delivered stillborn.

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“I know a lot of people that are very sad about the stillbirth of the second cub,”  senior curator Brandie Smith said. “But … I have nothing but joy that we have one cub that is very healthy and doing well.”

The cub has a steady heartbeat and is nursing well, said the zoo’s chief veterinarian, Suzan Murray.

The zoo doesn’t yet know the sex of the cub, which will take 2-3 weeks to determine based on a DNA sample.

On Friday, the zoo announced that Mei Xiang’s water broke, and then just over an hour later the cub was born.

“Mei Xiang picked the cub up immediately to begin cradling & caring for it,” the zoo said on its feed. “The cub is vocalizing.”

The 15-year-old panda went through five false pregnancies between 2007 and 2012, reports The Washington Post. She also lost a newborn female cub last September.

“The best indicator of somebody who’s going to give us a healthy panda is one who most recently had one,” zoo director Dennis Kelly told the Post. “She’s a very healthy animal … She’s back on track.”

You can check out the new mother and cub at the National Zoo’s live streaming Giant Panda Cam.

Photo: The surviving cub weighed in at 137 grams (about 4.83 ounces) during its first exam by zoo staff. Credit: Courtney Janney, Smithsonian’s National Zoo