The veterinarian guessed that the young female cheetah on the operating table was still carrying cubs. She had delivered one earlier, and now, seven hours later, she was still so big. There had to be more.

And if there were, and they were stuck, they and their mother could be in danger of dying.

So the National Zoo’s Copper Aitken-Palmer quickly ran her stethoscope over the anesthetized animal’s belly. Sure enough, there were the telltale rapid heartbeats of cubs. But how many? And could they be saved?

Thus began the zoo’s dramatic struggle last month to preserve the lives of a litter of four cheetah cubs and their mother.

It unfolded over two days like a medical thriller. Aitken-Palmer did an emergency Caesarean section on the mother cheetah, and keepers performed CPR for hours on the newborns, using thumbs and fingers.

In the end, only two of the one-pound cubs lived, but the zoo said it had done its best, and Wednesday the surviving cubs made a brief media appearance in Washington.

Looking scraggly but healthy, they wriggled and chirped as they were bottle-fed by two keepers.

“It was one of the most amazing things I’ve ever seen,” said Adrienne Crosier, cheetah biologist at the Smithsonian Conservation Biology Institute in Front Royal, Va., where the effort to save the cheetahs took place.

“They were really cold, so we were trying really hard to warm them up,” said Crosier, who worked on one of the cubs that died. “They’re just kind of skin and bones at that point . . . little, fuzzy, wet, matted.”

The battle to save the cubs began April 23, an unusually cold day with snow falling around Front Royal.

About 9 a.m., a 5-year-old cheetah named Ally, a first-time mother, delivered a male cub in an unheated enclosure at the institute’s nine-acre Cheetah Science Facility in the foothills of the Blue Ridge Mountains.

But instead of cleaning and nursing the cub, Ally abandoned it — something fairly common for first-time cheetah mothers in captivity, the zoo said.

Keepers waited to see whether she would return to the cub, but they grew increasingly worried about the cold. “It was likely right around freezing,”said Aitken-Palmer, the institute’s head veterinarian.

She said zoo officials hesitated to intervene, fearing that the cub then wouldn’t be accepted by the mother. But, finally, keeper Lacey Braun stepped in to retrieve the cub and save its life.

“He was frozen stiff and not responsive,” Aitken-Palmer said. The cub, which survived, was taken to the facility’s hospital and placed in an incubator.

Meanwhile, the staff kept an eye on Ally, who still looked extremely pregnant. Cheetahs can have one or multiple cubs. Ally, an 80-pound animal, had put on about 16 pounds since she became pregnant over the winter. “I figured there were a few in there,” Aitken-Palmer said.

Around noon, however, the cheetah’s contractions, which the keepers could see, seemed to stop. Suspecting there were more cubs, and concerned about the situation, Aitken-Palmer called a cheetah expert friend in Florida and was told that if too much time passed the mother and any unborn cubs could be in trouble.

“The concern is that if the cubs . . . are stuck in some way in the birth canal that they can’t come out, then they’ll die,” Aitken-Palmer said. “If the cubs die, and she still cannot push them out, the mother’s at risk.”

Toward evening, the zoo staff realized something had to be done. Aitken-Palmer anesthetized Ally with a dart gun, using drugs that would least affect the cubs.

The animal was taken to a hospital operating room, where the veterinarian heard the cubs’ rapid heartbeats and took an X-ray to see how many were there.

“You could see the spines, the skeletons of . . . three cubs,” she said.

Now they had to hurry.

“Time is not on our side,” she said. “As soon as she’s anesthetized, we have to get those cubs out immediately. . . . We’re on the clock.”

She went ahead with the C-section, which she figured would be necessary. She had done them on other animals but never on a cheetah.

It’s a delicate procedure, she said. You want to extract the cubs safely and quickly but with minimal damage to the mother.

Six extra staff members had been called in to help with the cubs. The operation started about 8 p.m. The first cub, a female, was extracted. Two males followed. They were big cubs. The staff dried them off and began working on them.

It was tense and exhausting. Aitken-Palmer could hear her co-workers exulting over progress or lamenting setbacks as they worked, while she tended to the mother. The team used drugs, oxygen and CPR.

“You have your thumb on one side and your fingers on the other, and just squeeze, kind of thing,” she said.

The first cub out began to breathe and squeal and move and was placed in an incubator.

“The second one would take a breath, but not routinely,” Aitken-Palmer said. “We worked on that one for two hours, because he still had a heartbeat the whole time. It just wasn’t happening. . . . He was just going what we call ‘agonal.’ . . . So we just decided to stop with him at that point.”

“The last one out never really responded,” Aitken-Palmer said. “I’m not sure that one ever really took a breath at all.”

The team worked until about 2 a.m.

On May 18, the surviving cubs were moved to the zoo’s main campus in Woodley Park, where keepers were feeding them around the clock every few hours.

Four cheetah litters have now been born at the Front Royal site, and two have been born in Washington since 2004, the zoo said. With the addition of the cubs, the zoo’s main facility has six cheetahs.

Cheetahs are the fastest animals on land, reportedly capable of running up to 70 mph. They are also known for their beauty and grace, and their inability to roar. Charlemagne, Genghis Khan and the ancient Egyptians are said to have kept them as pets.

There are probably about 10,000 surviving in the wild, mostly in Africa, the zoo said.

They are considered vulnerable by the International Union for Conservation of Nature.

Crosier said the cubs won’t be returned to their mother because she would not recognize them as hers. They will be “hand-raised” by keepers and will be reared together for the next 20 months.

“We never really want to do hand-raising because that impacts their ability to act like a normal cheetah when they’re an adult,” Aitken-Palmer said. “But it’s better than the alternative.”

Ally, meanwhile, has had a rough recovery. She was in intensive care for a week and later reopened her incision. She had to be anesthetized and sewn up again. “We were very worried about her,” Crosier said.

But she is now out of the hospital and is almost fully recovered: “She’s not 100 percent, but she’s doing well,” Crosier said.

The two cubs are thriving, although they won’t make their official debut until later this summer.

Reflecting on the events, Aitken-Palmer said: “You have sort of a mixture of feelings, because you want to save all of them. That’s always what we want.”