Pandas' Amorous Romp Concludes Scientifically

By Debbi Wilgoren
Washington Post Staff Writer
Monday, January 19, 2009

While most of Washington was focused on the upcoming presidential inauguration, the capital's famous giant pandas were attempting to create a little news of their own.

The National Zoo released a statement yesterday saying that Mei Xiang and Tian Tian had tried to mate "throughout the day Thursday," apparently without success.

"Because competent mating did not occur," the zoo statement said, veterinarians anesthetized both pandas on Saturday, collected semen from Tian Tian and inserted it into Mei Xiang's uterus.

Not very romantic, perhaps, but when it comes to panda procreation, romance is beside the point. Giant pandas, which are endangered in the wild, mate for only one or two days a year, and scientists believe there is only one day each year when a female panda is able to conceive.

So when zoo staff saw the pandas emit mating calls and display other pre-mating behavior Jan. 9, they began monitoring the hormone levels in Mei Xiang's urine. When the levels suggested that she had ovulated, the vets knew it was time to act.

Mei Xiang and Tian Tian produced one cub, Tai Shan, through artificial insemination in 2005. The cub drew record crowds to the zoo, and the three pandas remain an incredibly popular attraction for locals and tourists alike.

But attempts to impregnate Mei Xiang failed in 2002, 2003, 2004, 2007 and 2008. So it seems premature, to say the least, to buy cigars or birth announcements based on the events of the past several days.

Like everything else having to do with making panda babies, determining whether a female panda is pregnant is extremely complicated. Pandas often have pseudo-pregnancies, in which they display the signs of pregnancy but then turn out not to be expecting after all.

Scientists say they have no way to know whether an artificial insemination was successful until the end of the gestation period, which can last from 90 to 185 days.

Mei Xiang and Tian Tian were separated immediately after the insemination, and will be kept in separate enclosures for the next few months, until Mei Xiang either delivers a cub or tests show conclusively that she is not pregnant, zoo officials said.

This year's mating attempts occurred unusually early in the year, according to the zoo. Typically, Mei Xiang has ovulated in March or early April.

Although it might be tempting to attribute the change to the inaugural excitement that has swept the city, zoo officials said they will study numerous other factors and try to "shed new light on what triggers the reproduction in this endangered species."

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