Zoo cheetah cubs born in race against the clock 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 are scheduled to make a brief media appearance in Washington. "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 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 during her pregnancy. "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.