The Stork Won’t Visit National Zoo Giant Pandas This Year
August 22, 2003
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The Stork Won’t Visit National Zoo Giant Pandas This Year
--The National Zoo's giant panda, Mei Xiang, is not pregnant--
The Smithsonian’s National Zoological Park’s female giant panda is not pregnant this year, but Zoo scientists said they have collected significant hormonal, behavioral and other data that will help them – and other researchers studying giant pandas – better understand the reproductive nature of these endangered animals.
Mei Xiang mated with National Zoo male giant panda Tian Tian in a very brief, 15-second encounter on April 4. Since that time, Zoo researchers have been recording and studying Mei Xiang’s hormone levels, behavioral data and the results of weekly ultrasounds in an effort to learn more about Mei Xiang’s condition and panda reproduction.
Female giant pandas always undergo “pseudopregnancies” when they ovulate but fail to conceive. During a pseudopregnancy, hormonal changes and behaviors are nearly identical to a true pregnancy. Because of this phenomenon, it is difficult to determine if a panda is pregnant.
After months of high hormone levels associated with
pregnancy or pseudopregnancy, on Aug. 10, Mei Xiang’s hormone
levels began to decline, which is an indication of either
an imminent cub birth or the end of a pseudopregnancy. After
the hormone levels reached normal baseline – and remained
that way for 48 hours – Zoo researchers determined
that Mei Xiang had experienced a pseudopregnancy.
Visitors to the National Zoo Web site have been
tracking the changes in Mei Xiang’s hormone
levels, which were updated daily.
Giant Panda Reproduction Facts
- Breeding maturity usually occurs between the ages of 5 and 7.
- Female giant pandas give birth between 95 and 185 days after mating; a result of the reproductive phenomenon known as “delayed implantation.”
- Twins are common, but only one usually survives in the wild.
- Cubs are born pink, blind, and with sparse white hair.
- Newborn cubs weigh 3 to 5 ounces and are about the size of a stick of butter.
- Average captive-born giant panda cub survival rate is 67 percent.
- Except for a marsupial, a giant panda cub is the smallest mammal newborn relative to its mother’s size.
- Cubs do not open their eyes until they are 6 to 8 weeks old, and are not mobile until after 3 months.
- Cubs, which nurse for eight to nine months, are nutritionally weaned after one year, and socially weaned after as many as two years.
- National Zoo male giant panda Tian Tian is 6 years old. His name means “more and more.”
- Mei Xiang is 5 years old, and her name means “beautiful fragrance.”
- Tian Tian and Mei Xiang arrived at the National Zoo on Dec. 6, 2000. They were born at the China Research and Conservation Center for the Giant Panda in Wolong, Sichuan Province of China.
- Giant pandas are critically endangered. There are approximately 1,000 left in the wild and some 150 in zoos and breeding centers around the world.
