Skip in Skip x Embed x Share CLOSE The second-born panda cub born to Mei Xiang died at the Smithsonian National Zoo. The cub went into cardiac arrest and the workers were unable to revive him. The larger cub, born first, appears to be strong and healthy. VPC 
 
 In this handout provided by the Smithsonian's National Zoo, one of two newborn Giant Pandas born August 22 is cared for by a member of the panda team at the Smithsonian's National Zoo and Conservation Biology Institute on August 24, 2015, in Washington, DC. (Photo: Getty Images) 
 
 The smaller of twin giant panda cubs born Saturday died Wednesday afternoon at the Smithsonian's National Zoo in Washington, D.C., officials said. 
 
 Skip in Skip x Embed x Share CLOSE One of the twin panda cubs at Smithsonian's National Zoo in Washington, D.C., died just days after its birth. Video provided by Newsy Newslook 
 
 The larger cub, born first, appears to be "strong, robust, behaving normally" and is with its 17-year-old mother, Mei Xiang. 
 
 "We have one healthy panda and we remain optimistic about that panda's future," the zoo's chief veterinarian, Donald Neiffer, said at a news briefing. 
 
 After spending the night with its mother, the smaller cub, which weighed just 3 ounces at birth, appeared weaker Wednesday morning and was having trouble breathing, he said. Veterinarians pumped oxygen into the incubator and gave the cub aerosolized antibiotics and medication to break up mucus in its lungs, to no avail. 
 
 “Despite extreme efforts on the part of our dedicated staff, we weren’t able to change things,” Neiffer said. 
 
 The cub went into respiratory and cardiac arrest at about 2 p.m. Veterinarians performed gentle CPR for a few minutes until Neiffer ordered them to stop. 
 
 He said the cub's death "was very quick.” 
 
 A necropsy will be performed to try to determine exactly why the cub died. 
 
 Mei Xiang, who was artificially inseminated in April, gave birth to the twins five hours apart Saturday. The first cub was born at 5:34 p.m. and weighed 4.8 ounces. The second was born at 10:07 p.m. 
 
 We are sad to report that the smaller of the two panda cubs has died. We will continue to provide updates on social media w/ #Pandastory. — National Zoo (@NationalZoo) August 26, 2015 
 
 After their births, the zoo announced that it would be rotating the cubs so that one could be with the mother at a time. Staffers said they would switch the cubs about every four hours so each had time to nurse and have quality time with Mei Xiang. The other cub would be bottle fed and kept warm inside an incubator. 
 
 The zoo said Sunday that veterinarians tried to swap the cubs around 11 p.m. but that Mei Xiang would not put down her first-born cub. The smaller, second-born cub was cared for until 7:05 a.m. Monday, when they successfully swapped the cubs. 
 
 Tuesday, the National Zoo tweeted that vets hadn't been able to swap the cubs since 2 p.m. Monday, but also reported that the smaller cub's "behaviors are good; still high-risk time." 
 
 Haven’t been able to swap cubs since 2p 8/24.Mei has larger cub.Smaller cub’s behaviors are good;still high-risk time pic.twitter.com/FrEG2lYfEz — National Zoo (@NationalZoo) August 25, 2015 
 
 Officials said earlier that the cub had shown some signs of regurgitation, which could lead to aspiration. Veterinarians were administering antibiotics to prevent possible infection, and keeping the smaller cub hydrated by alternating an infant electrolyte solution with formula and administering fluids under the skin, according to WUSA-TV. 
 
 It was the third time in three years that Mei Xiang has lost a cub. One was stillborn in 2013, and another died in 2012 after six days. 
 
 She has two other surviving cubs, born in 2013 and 2005. 
 
 Contributing: Michael Winter, USA TODAY 
 
 Photos: Giant panda gives birth to two cubs at National Zoo 
 
 Read or Share this story: http://usat.ly/1EkF0f0 ||||| One of the newborn panda cubs at Washington D.C.’s Smithsonian National Zoo is sparking concern from veterinary staff because its weight has been fluctuating and it has been suffering from digestive issues, according to officials from the Zoo. 
 
 Mei Xiang, the mother of the two cubs born on Saturday, has been refusing to allow the zoo’s “panda team” to switch out the two cubs from her care since 2 p.m. Monday afternoon. 
 
 The panda team is caring for the smaller cub, but is worried about its fluctuating weight. The cub has shown signs of regurgitation, which can lead to breathing issues in such a small animal, though staff has not seen any indication of such problems. 
 
 To manage its condition, the team is bottle- and tube-feeding the cub as well as administering antibiotics and electrolyte solution through formulas and under the skin to ensure it gets proper fluids and nutrients. 
 
 The little cub’s behaviors are good and the team will continue efforts to swap the cubs about every four hours. 
 
 Haven’t been able to swap cubs since 2p 8/24.Mei has larger cub.Smaller cub’s behaviors are good;still high-risk time pic.twitter.com/FrEG2lYfEz — National Zoo (@NationalZoo) August 25, 2015 
 
 The larger cub is in Mei’s care and zoo officials say the cub is doing well. 
 
 Veterinarians say they are still in a high-risk time in their care for the cubs. 
 
 Veterinarians must switch out the cubs from the mother’s care because twins are often overwhelming to the mother. The panda team will alternately swap the cubs, allowing one to nurse and spend time with Mei Xiang while the other is being bottle fed and kept warm by zoo staff. 
 
 The zoo’s “panda team” consists of National Zoo staff, Asia Trail keepers, a panda keeper from Zoo Atlanta and additional veterinarian staff. ||||| In this photo provided by the Smithsonian's National Zoo, one of the giant panda cubs is examined by veterinarians after being born at Smithsonian's National Zoo on Saturday, Aug. 22, 2015, in Washington. The National Zoo in Washington says its adult female panda has had twins. 
 
 The National Zoo's giant panda, Mei Xiang, gave birth to twins Saturday, almost two years to the day after giving birth to her daughter, Bao Bao. 
 
 Mei Xiang was seen picking up and licking her first cub at 5:35 p.m. Saturday, live on the zoo's panda cams. The cub could be heard squealing just after the birth, which zoo officials called a good sign. 
 
 The second cub was born just after 10 p.m. As is the zoo's practice, one of the two cubs was retreived from Mei Xiang's enclosure and placed in an incubator. That cub appears to be in good health, according to a post on the zoo's Facebook page. 
 
 Zoo veterinarians had not yet retrieved the other cub from Mei Xiang's enclosure late Saturday night. They will closely monitor both mom and that baby on the panda cams, waiting until they can retrieve the cub without distressing mom or cub. 
 
 Best Look Yet At New Panda Cub 
 
 News4's Darcy Spencer has new video from the Panda Cam of the first of two brand new cubs who arrived Saturday at the National Zoo. (Published Sunday, Aug. 23, 2015) 
 
 The time after the birth is critical for bonding, but this is "still a very fragile time" for the cubs, said National Zoo Director Dennis Kelly. 
 
 In 2012, a female cub died a week after her birth. "We are very excited but we are very cautious," Kelly said at a press conference after the first birth. 
 
 There's a protocol for twin panda births, which happen about 50 percent of the time in the difficult and often-disappointing world of giant panda procreation. The Zoo's panda team will swap the cubs into the enclosure, allowing one to feed and bond with Mei Xiang while the other is bottle-fed and cared for in an incubator, the Zoo said. 
 
 The births came quickly on Saturday. Earlier that day, the Zoo's panda team said in a Facebook post that Mei is "restless, having contractions, body licking, and remains in her den." The team said those behaviors are consistent with an imminent birth. 
 
 Two Tiny Pandas Born at National Zoo 
 
 Around 4:40 p.m., the zoo said the panda team confirmed that Mei Xiang's water broke. 
 
 Zoo personnel monitored Mei through their panda cams, which were overloaded from time to time due to the popularity of the pandas. 
 
 Mei was inseminated April 26 and 27 with frozen sperm from Hui Hui, a panda living in China, and with sperm from the zoo's male giant panda, Tian Tian, the Smithsonian Conservation Biology Institute said. 
 
 Watch the Moment Giant Panda Gives Birth 
 
 Giant Panda Mei Xiang gives birth to new cub at the National Zoo! (Published Saturday, Aug. 22, 2015) 
 
 On Aug. 10, Mei's hormone levels were on the rise as she began to show typical signs of pregnancy or pseudopregnancy, including spending more time in her den, sleeping more, body licking and cradling objects. 
 
 On Tuesday, the National Zoo closed its giant panda exhibit as Mei entered her final final phase of her pregnancy due to her sensitivity to noise. Wednesday, Zoo vets detected her fetus on an ultrasound -- the first time they had ever seen a fetus on ultrasound, since Mei Xiang usually doesn't cooperate with scans. 
 
 At the time, zookeepers thought they might have spotted a second fetus, but they couldn't be sure, they said at the afternoon press conference. 
 
 This is the first time the National Zoo has had newborns and an older cub -- in this case, 2-year-old Bao Bao -- at the same time. 
 
 Top 10 Bao Bao Moments 
 
 Mei Xiang has previously given birth to four cubs, two of whom survived: male Tai Shan, who was born at the zoo in 2005 and now lives in China, and female Bao Bao, who still lives at the National Zoo. In addition to the female cub that died in 2012, another female cub, Bao Bao's twin, was stillborn. 
 
 Tian Tian fathered all four cubs. It's not yet known which of the two possible fathers sired these cubs. 
 
 Following Chinese tradition that celebrates 100 days of life, panda cubs are named 100 days after their birth.
– A heartbreaking update to the story of Mei Xiang's panda cubs: The smaller twin born to the National Zoo panda has died. The new mom had started ignoring the smaller cub in favor of nursing the bigger one, and the zoo tweeted today, "We are sad to report that the smaller of the two panda cubs has died. We will continue to provide updates on social media w/ #Pandastory." The good news: The zoo says the larger cub seems "strong, robust, behaving normally," USA Today reports. "We have one healthy panda and we remain optimistic about that panda's future," said the zoo's chief veterinarian at a press conference. Click to read about how the zoo had been attempting to swap out the cubs with their mom.