Science lends hand to pandas

Artificial insemination is playing a role in more panda pregnancies.
Washington Post
WASHINGTON -- The National Zoo's giant panda cub, Tai Shan, didn't just happen -- he was brought to you by scientists who spent years studying the intimate details of black-and-white bear biology before they mastered artificial insemination.
A recent surge in giant panda science is helping zoos get more animals pregnant, diagnose when they are expecting and put to rest the long-held belief that pandas are poor breeders. The research is producing insights into how pandas communicate, how mothers raise their young and how the animals look for food.
The ultimate goal is to increase the giant panda's chances in the wilds of China, where only about 1,600 remain, threatened mainly by the loss of bamboo forests to logging and development. Scientists are studying the panda's basic survival needs and are trying to build up the number of captive animals so that some could be set loose in potential panda territory.
Money for the studies has come largely from the four U.S. zoos that have giant pandas -- including the National Zoo, where Tai Shan went on public display Thursday.
"I am not sure we know of any endangered species where we have this amount of information," said National Zoo senior scientist David Wildt.
Making headway with China
In a recent interview, a high-ranking Chinese wildlife official, Yan Xun, underscored the cooperation between U.S. and Chinese scientists: "We have achieved a lot of accomplishments," he said.
Tai Shan's birth in July was the result of years of research efforts. Many experts believed that giant pandas were poor breeders because they seldom got pregnant in zoos and because females are fertile only two or three days a year. But that idea crumbled after U.S. and Chinese scientists examined dozens of captive pandas in the late 1990s and found most biologically fit to breed.
"We have every reason to believe that pandas in the wild are doing all right as far as opportunities for pregnancy are concerned," said Donald Lindburg, head of the giant panda team at the San Diego Zoo, where three cubs have been born. "This is more of a captive phenomenon."
Artificial insemination is one way around the obstacle of persuading pandas to breed naturally. National Zoo scientists have been working since the 1980s on monitoring hormone changes to tell whether a female is fertile. Scientists there and at other zoos increased the research in the late 1990s, when China began lending panda pairs to U.S. animal parks.
National Zoo keepers trained their female, Mei Xiang, to sit still for medical tests. Scientists created a mobile lab to track hormone changes in her urine and improved testing to get results faster. They watched for behavior changes that indicated she was ready.
"Short of crawling inside her abdomen," reproductive scientist JoGayle Howard said, "I don't think you can get any better timing."
Zoo scientists hoped that Mei Xiang and the male panda, Tian Tian, would mate naturally last spring, but when that did not happen, they stepped in as the female's short window of fertility was about to close. Howard e-mailed regular updates of Mei Xiang's test results to San Diego Zoo scientists, who suggested a specific time to perform artificial insemination.
With Mei Xiang under anesthesia the morning of March 11, Howard employed a tiny laparoscope with a light to perform the procedure, the first time that particular type of instrument was used on a giant panda.
"It's remarkable," Lindburg said. "They had one vial; they had enough sperm for one insemination. They had a single event, and they nailed it."
Panda breeding
Zoo managers would prefer that pandas breed on their own, and one line of research is trying to foster that. A major discovery is that pandas get to know each other through their noses. A male panda can tell whether a female is in heat by sniffing her urine or the scent marks she leaves behind. Each panda has an individual scent.
In the past, zoos raised males and females separately, putting them together only for mating. Often, that resulted in fights, not cubs. "When animals are introduced for breeding, they need time to become familiar with each other, scent-wise, before they are put together," said Rebecca Snyder, curator of giant panda research at Zoo Atlanta.