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April 12, 2005: PREGNANT?
April 10, 2005: Panda love tryst at San Diego Zoo
November 5, 2003: Record 16 pandas born this year
April 29, 2003: In China, Panda Mating Season Breeds Hope
April 12, 2005: PREGNANT?
Pandas' sex lives are subject of keen interest
WASHINGTON
- Celebrity pregnancies are media magnets. But no human movie star has had
to endure a Web site displaying her hormone charts, regular updates on her
behavior and live shots of her bedroom interactions with the man in her life.
Then again, the survival of the species is unlikely to depend on the resulting baby, as is the case with Mei Xiang and her mate, Tian Tian, the stars of the National Zoo's giant-panda exhibit.
The fascination with the pandas' sex lives has been a springtime Washington ritual for many years, and the zoo is using its Web site to give the nation a front-row seat for the giant pandas' continuing pregnancy story.
Giant pandas experience pseudopregnancy, meaning that their hormones and behavior mimic those of a real pregnancy. So without a definitive ultrasound there is no way to know whether Mei Xiang (pronounced may-SHONG) is pregnant until there is a birth or until hormone levels return to normal.
Because the pair did not successfully mate, Mei Xiang, who is 6 years old and weighs about 250 pounds, was inseminated with sperm from Tian Tian (pronounced t-YEN t-YEN) on March 11. And this time, said Susan Lumpkin, the communications director of the Friends of the National Zoo, the scientists think they got it "pretty perfect."
Speculation about Mei Xiang's pregnancy has drawn huge crowds to the zoo and to Lumpkin's giant-panda Web site. But pandas' pregnancies are not apparent because the baby is so small. The only way to know whether Mei Xiang is pregnant is to wait for a birth in three to six months.
The zoo plans to post ultrasounds, Web shots and other information as they come in.
The best time to tune in is from 6:30 to 7:30 a.m. CDT, when the pandas are usually most active, and at 11 a.m. and about 2:30 p.m., before the pandas head back inside, said Matt Olear, a spokesman for the friends organization.
From the New York Times, Courtney C. Radsch
April 10, 2005: Panda love tryst at San Diego Zoo
Gao Gao, Bai Yun should bear cub in about four months
SAN DIEGO (AP) - Giant pandas Gao Gao and Bai Yun retired to their favorite
spot under a few bushes and mated over the past two days, marking the only
successful natural insemination of a panda this year in the United States,
San Diego Zoo officials said Saturday.
It was the second mating for the giant pandas at the San Diego Zoo, which closed its panda exhibit to visitors and pointed its Internet panda cam elsewhere for the occasion. Bai Yun gave birth in 2003 to Mei Sheng and did not mate last year because she was nursing the cub.
Bai Yun will likely give birth to her third cub in about four months, said Don Lindburg, the zoo's giant panda conservation team leader.
"We do have adults of proven fertility," he said Saturday. "The chances are pretty high that there will be a litter in late summer."
Lindburg said Bai Yun had displayed the signs of being receptive to mating in recent days, including yipping and raising her tail, walking through water -- creating a "wet dog" scent that researchers believe may attract male pandas -- and scraping pine tree bark onto her head and face.
"It's getting her perfume on for the date," Lindburg said. "It's really quite a sight, because she backs up against the tree, sits and scrapes the bark onto her head. Then she rubs her hair, her face. It's very catlike."
Gao Gao responded by becoming visually aroused and trying to tear through the wire mesh gate that separates the two most of the year. Zoo officials lifted the gate Friday morning to let the mating begin. The two, both 13 years old, spent about 15 minutes mating Friday in the same spot on Gao Gao's side of the exhibit where they mated in 2003.
Then, Lindburg said, "They pretty much ate and slept. They were pretty content to sleep most of the day, and try it again this morning."
The pandas mated for about a half-hour Saturday in the same spot and may try again Sunday. Researchers detected live sperm in Bai Yun's urine and determined that she had been successfully inseminated.
Pandas are used to living alone most of the year and spend most of the mating time "fumbling around and trying to become properly aligned," Lindburg said. Mei Sheng has been moved to another section of the zoo's exhibit, which will likely reopen Monday, he said.
There are three other panda pairs in U.S. zoos, including two in Memphis, Tenn., which are not expected to mate this year. Natural mating attempts in recent weeks were unsuccessful at Zoo Atlanta and the National Zoo in Washington, D.C., though females at both zoos were artificially inseminated.
The amorous tendencies of the pair in San Diego are a relief for zoo officials who tried unsuccessfully from 1996 to 2002 to get Bai Yun to mate with Shi Shi, the zoo's first male.
Shi Shi "was not at all interested in mating during the female's period of solicitation. He would respond to her aggressively," said Lindburg, who has overseen the zoo's pandas since they first arrived in 1996.
Artificial insemination resulted in the 1999 birth of Hua Mei, the first giant panda to survive more than four days in the U.S.
About 1,600 giant pandas live in the wild in their native China and another 200 live in captivity there. Less than two dozen pandas live in captivity outside China.
Under the loan agreement with China, all pandas born at zoos outside the country must be returned to China after the animals mature.
From the Monterey County Herald and the Associated Press
November 5, 2003: Record 16 pandas born this year
A record 16 giant pandas have been born in captivity this year, the head of China's panda breeding programme says.
They include twins born in Japan and a cub born in California - to mothers lent to zoos by China.
Threatened with extinction in the wild, captive breeding programmes, including artificial insemination, are seen as vital to save giant pandas.
Only about 1,000 of the animals remain in the wild, feeding on bamboo in the Sichuan mountains of south-west China.
A total of 29 pandas were inseminated naturally or artificially in the spring and they gave birth to 19 pandas in the autumn, of which two were stillborn and one failed to survive, said Zhang Zhihe, head of China's Giant Panda Breeding Technology Committee.
He said the survival rate of 84% was good news for the protection of pandas.
About 140 giant pandas live in zoos and research centres worldwide.
Twelve cubs born in captivity survived in 2001 and 10 in 2002, the Chinese official news agency Xinhua reported.
Female pandas are only able to become pregnant once a year - for only about two days - and give birth to just one or two cubs at a time.
More than 60% of male pandas in captivity show no sexual desire at all, while just a 10th of them will mate naturally, according to Xinhua.
From BBC News
April 29, 2003: In China, Panda Mating Season Breeds Hope
This spring, panda researchers in China are closely watching Da Shuang, a five-year-old female panda.
If Da Shuang is ready to mate, she'll show signs like scent-marking, restlessness and characteristic bleating sounds.
Researchers also monitor Da Shuang's urine for signs that she is ovulating. Females can conceive just once a year, for only three days.
Da Shuang lives at the Chengdu Research Base of Giant Panda Breeding, a zoological research center outside Chengdu, in the central Chinese province of Sichuan.
The Chengdu Base has 32 resident pandas—one of the highest concentrations of pandas anywhere. Pandas, perhaps the world's most coveted animals, are also among the most endangered.
"In the past, Chinese people did not pay much attention to animals or the environment," says Hu Jin Chu, a zoologist at the Chengdu Base who is known as "the father of panda research."
"But now with all the economic growth the society is learning a lot about nature, especially the kids … who like pandas very much because they are from China."
The Chengdu Base, in addition to its scientific mission, is open to the public and has become one of China's premier tourist attractions.
Only about 1,000 pandas remain in the wild. Panda range once extended from eastern and southern China into North Vietnam and Myanmar.
A Frozen Generation—A Panda Sperm Bank
But habitat loss and human encroachment have limited the wild panda population to about 30 wilderness reserves primarily within the Sichuan province.
Zhang Zhihe, a genetics specialist and the director of Chengdu Base, is marshaling scientific resources to help grow the panda population, cub by hard-won cub.
Among the challenges: Even if Da Shuang is ready to mate, the male's performance is not guaranteed.
Males in captivity either show a serious lack of interest or are incompatible with the females and become aggressive.
When natural mating fails, researchers may try artificial insemination with frozen sperm.
At Chengdu, Zhang's team can draw on the largest giant panda sperm bank in the world—samples from 17 animals are represented here, including one that died 12 years ago.
Zhang's technicians also freeze the cells of giant pandas in liquid nitrogen
for a genomic databank that allows the researchers to track parentage and
ensure genetic diversity of any future population.
China holds about 130 pandas in captivity. The three largest panda centers
are Chengdu, the Beijing Zoo and Wolong.
China and the United States are collaborating closely on developing genetic profiles for the captive population.
"The goal is to establish a meta-population" in which the populations at the three centers could share genes, says David Wildt, head of reproductive sciences at the Smithsonian National Zoological Park in Washington.
Raising Twins
"Sharing genes keeps the panda population vigorous. If the sharing doesn't happen soon then each institution will start mating relatives (causing inbreeding), and that won't be good."
Artificial insemination may save the captive breeding program. Success rates continue to improve, says Zhang, and so do the cubs' chances of survival.
Two decades ago the Chengdu base started with only five captive-born pandas. Since then, 50 litters have produced 78 cubs—44 of them have survived.
Seven months ago today, three pandas were born in Chengdu.
All the world's science, however, can't guarantee the survival of a newborn.
About 60 percent of the time, pandas give birth to twins but the mother cares
for one and abandons the other completely.
"Only one survives," Zhang says. "We guess this is a form of
natural selection."
But at Chengdu, veterinarians have mastered a way to save them both. They stealthily take one newborn, place it in an incubator and feed it with a bottle of formula.
Later on, when the mother is asleep, a caretaker snatches the cub and replaces
it with another.
"I've seen them do it," Wildt says. "The mother doesn't even
wake up—it's amazing."
One day, Chengdu hopes to expand with space for a halfway house that will help the pandas return to the wild.
First the researchers need 60 to 80 pandas on hand. That means at least several more years of breeding pandemonium.
Meanwhile all eyes are on Da Shuang.
From National Geographic Today, Andrew Paterson and Patty Kim