WASHINGTON — The National Zoo's panda parents, Mei Xiang and Tian Tian, have another son.
The zoo announced Friday that the surviving panda cub is male and the son of the zoo's male panda Tian Tian. Mei Xiang gave birth to fraternal twins Saturday, but the smaller cub — also a male fathered by Tian Tian — died Wednesday.
The surviving cub appears to be healthy and is gaining weight under his mother's care, said Associate Director for Animal Care Sciences Brandie Smith. The little cub's weight increased about 16 percent in the last two days.
"We hear those big, squawking lungs, and we're pretty sure that it's doing well," Smith said. "Also the best way to describe it now is plump. You can see its fat little belly when it's on mom. So we know that it's drinking milk. We know that it's doing well."
Reproductive biologist Pierre Comizzoli said there was no preference for a male or female cub in adding to the panda population.
Pink, hairless and blind, newborn cubs weigh three to five ounces at birth. Mei Xiang weighs more than 700 times as much.
Tian Tian is the father of Mei Xiang's other cubs, daughter Bao Bao and son Tai Shan. During this year's panda breeding, Mei Xiang was artificially inseminated with semen from Tian Tian and a panda in China named Hui Hui that was deemed a good genetic match.
The most likely cause of death for the smaller cub on Wednesday was complications from food getting into its respiratory system resulting in the development of pneumonia, officials said.
The trouble likely arose from the delicate process of hand-feeding the tiny cub when Mei Xiang could not handle both twins and stopped feeding one of them.
"The staff is devastated," Smith said. "When you have twins, it's a blessing and a terror because you know that if you are hand-raising a cub ... there is a very real risk of aspiration pneumonia."
The animal keepers had no choice but to try hand-feeding the cub, Smith said.
Mei Xiang struggled to handle both twins for the first 24 hours but eventually gave up and set one aside. The smaller cub would have died without the keepers' intervention.
Hand-feeding is extremely delicate because the cubs are so tiny. Bottle feeding seemed to go well after some trial-and-error in finding the right nipple size. But then keepers noticed some regurgitation. They started giving the cub antibiotics to try to prevent illness.
"Once an animal becomes ill, things become more difficult," Chief Veterinarian Don Neiffer said. "It's hard to come back."
The National Zoo is one of only four zoos nationwide to have pandas, which are on loan from China. The Washington pandas have a history that makes them closely watched.
The zoo's first pair of pandas, Ling-Ling and Hsing-Hsing, were a gift from China following President Richard Nixon's historic 1972 visit to the country. The pair had five cubs while living at the zoo but none survived.
The zoo's current adult pandas, Mei Xiang and Tian Tian arrived in 2000 and are currently on loan through the end of 2015. The pandas belong to China as do any cubs they have. Tai Shan, 10, returned to China in 2010. Bao Bao, who turned 2 on Sunday, still lives at the National Zoo.
The new cub is expected to make his public debut in January. He will share Mei Xiang's panda den for now but will eventually be separated to avoid fighting with mom as he grows up.
National Zoo: http://nationalzoo.si.edu/
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