For a few terrifying minutes Saturday night, keepers at the National Zoo thought their precious day-old giant panda cub might be dead.
The zoo's panda cameras appeared to show the vibrant, squirming cub of Friday now lying silent and unresponsive on the abdomen of its mother, Mei Xiang.
Memories of the death of the zoo's six-day-old panda cub last September came flooding back.
Then the keepers heard robust squealing coming from elsewhere. They realized - to their joy and sorrow - that what they were seeing on camera wasn't the first cub, but the stillborn body of a second cub.
"In the circle of life there are always joys and sadnesses," Don Moore, the zoo's associate director of animal care sciences, said Sunday.
As zoo officials recounted the tense moments of Saturday night, senior curator Brandie Smith teared up as she told of the "five minutes of pure terror," followed by relief when they realized what had happened.
When the dead cub was first spotted, "there was full-blown panic," Smith said. Keepers had not seen the second cub's birth. "All we saw was a cub that was not moving," she said.
"I know a lot of people that are very sad about the stillbirth of the second cub," she said at a Sunday morning news briefing at the zoo. "But I have to say that (after) those moments of pure sorrow and panic, especially after last year, I have nothing but joy that we have one cub that is very healthy and doing well."
"I am full of joy and happiness this morning," Smith said Sunday.
The whole time, Mei Xiang had the first cub tucked under her arm where keepers didn't notice it until it squealed.
The zoo Sunday released photos of the surviving cub, which showed a small, palm-size animal with pink skin that is already covered in short, white fur.
Zoo chief veterinarian Suzan Murray, who examined the cub, said it felt like a strong kitten, "much stronger than I had anticipated," she said. She said this was the first time she had held such a young giant panda.
The animal weighs 4.8 ounces, and its eyes are still closed. The zoo was able to get a mouth swab, from which DNA may be extracted and used to establish paternity. Mei, 15, was inseminated in March with semen from two giant pandas. The photos were taken during a physical examination after the cub was taken from its mother Sunday morning. In a delicate maneuver, one keeper distracted Mei Xiang with food, while another removed the squealing cub from under her arm.
The examination was conducted immediately outside the den.
Biologist and keeper Laurie Thompson had the unenviable task of returning the cub to a visibly agitated 240-pound bear that was standing up and "vocalizing" unhappily.
"So I knew I had to be very careful about putting the cub in," Thompson said. Her only protection was a pair of rubber gloves. Giant pandas have very powerful jaws and claws. "I didn't want to stick my hands right near her."
Thompson said she waited until Mei Xiang backed away from the bars of the enclosure. The keeper said she then squatted down, placed the cub on the floor inside the den, and withdrew.
Mei picked the cub up in her mouth and retreated to a corner of the den, content.
The whirlwind of events in the panda compound began Friday at 3:36 p.m., when the zoo's new high-definition panda cams captured Mei Xiang's water breaking. Moore said he thinks it was the first time that had been observed with a giant panda, and many experts had no idea that water broke in bears. It makes perfect sense, he said, but "we're learning a lot."
Less than two hours later, in an event caught live on the black-and-white cameras, Mei delivered the first cub. Mother and cub were carefully watched, and both seemed to be well. Keepers waited to see whether a twin might arrive, but after midnight, they concluded that a second cub was probably not coming.
Pandas often have twins, but they usually arrive within about six hours of each other. On Saturday, keepers twice tried to get the cub from the mother for an examination, but they were not able to distract her enough. Then, at about 7:30 p.m., the second cub was born, and for a few minutes, Mei groomed it, all while holding the first cub tightly under her arm.
"Her instinct would be just to pick it up," Murray said. "But then she's looking for cues from that infant" indicating that it was alive. "When she realized it wasn't alive, that's when she let it down."
Murray said the second cub's physical deformities were extensive. It was missing part of its upper skull, brain, eyes and the upper jaw. Stillbirths in giant pandas are extremely rare, and experts had heard of only three before this one. The second cub's birth 26 hours after the first also was highly unusual, zoo officials said.
Officials said a necropsy was conducted but that the results won't be known for several days. Zoo officials also do not know the surviving cub's sex. It will take two to three weeks before that is determined.
After an emotional weekend, Smith, the senior curator, said zoo officials plan to back off on Monday: "We are going to leave Mei Xiang in peace with her cub."