February 2, 2011
National Zoo Pandas Attempting To Mate
In a move almost guaranteed to quash romantic notions, onlookers watched intently from video monitors as two giant pandas at Washington DC's National Zoo were about to have their first date in a year.
The female panda Mei Xiang and her intended partner Tian Tian, are closely monitored in the hopes that they would produce a cub come spring. "That is the beauty of the panda breeding season. Everything happens in two or three days but it is always extremely intense," said Pierre Comizzoli, a reproductive physiologist at the National Zoo, to AFP.Mei Xiang, who is only fertile for a couple of days annually, began making sounds that zoo keepers recognized as fertility calls about two weeks ago, indicating that the time was near.
An expert from China, Tang Chunxiang from the China Conservation and Research Center for the Giant Panda in Wolong, arrived to consult with the US-based team in January. This last weekend, the two pandas, who spend nearly every other day of the year in separate spaces, were allowed to get close to each other.
The pandas have been a couple since 2000. Their one cub, Tai Shan, born in 2005, was conceived through artificial insemination. Before this year's breeding season, zoo keepers enrolled the bears in workout sessions to boost their stamina and build their muscles.
"We wanted them to be well-rested and in the best possible shape physically to breed naturally," said curator Brandie Smith. "And if there was anything we could do to enhance that success, then we did our best to apply it." AFP reports. Tian Tian's regime focused on training him to stand tall on his hind legs, while Mei Xiang was coaxed into lying across a large log in her cabin to improve her positioning.
"The main problem we've had with our male and female so far is that they were really not good at conceiving naturally, so the natural mating was not really good," Comizzoli remarked. Tang was "definitely able to detect exactly what was wrong with the positioning of the male and the female" that was preventing natural impregnation, he said.
Tian Tian, 13, gets few chances to improve on his technique so zoo experts were forgiving of his foibles. "Basically it is a lack of practice and a lack of confidence," said Comizzoli.
A panda's gestation can last 90-185 days. Hormone levels do not reveal anything early, and ultrasounds are difficult so zoo keepers will not know for months if Mei Xiang, who is 12 years old, was able to become pregnant.
"What is really frustrating with those bears is they are really huge, really fat and they have a really thick fur," explained Comizzoli. "They have a really tiny uterus and the cub inside is a really tiny cub so in comparison with other mammals it is really difficult to see something. If you do see something it is really toward the end of the pregnancy."
Mei Xiang and Tian Tian belong to China but came to the US National Zoo in 2000 for 10 years of research. Their stay was recently extended by a five-year deal but if they don't produce a cub soon, they may be exchanged for a younger couple. Considered an endangered species, scientists believe about 1,600 pandas exist in the wild, mainly in China, and there are about 300 in zoos around the world.
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