Handout photograph shows an ultrasound image of Smithsonian National Zoo giant panda Mei Xiang.
WASHINGTON (Reuters) - The National Zoo's giant panda Mei Xiang, who was showing signs of being pregnant, is actually carrying a developing fetus and could give birth in coming weeks, the Washington zoo said on Wednesday.
Veterinarians detected a 1.6-inch (4-cm) fetus during a Wednesday ultrasound of Mei Xiang, who is a star tourist draw in the U.S. capital, the zoo said in a statement.
"Today, we are cautiously optimistic," said Dennis Kelly, the zoo's director.
Veterinarians estimate that Mei Xiang could give birth early next week or possibly in early September, the statement said.
The zoo warned, however, that there is a substantial possibility that the fetus could be miscarried or resorbed, a process in which a fetus is broken down into components and dispersed in the panda's circulation.
Mei Xiang started showing a secondary rise in her urinary progesterone on July 20, a sign of pregnancy or a false pregnancy.
Mei Xiang was artificially inseminated on April 26 and 27. The procedures used frozen sperm from Hui Hui, a panda living in China, and fresh sperm from the National Zoo's Tian Tian, it said.
Mei Xiang is showing behaviors at the David M. Rubenstein Family Giant Panda Habitat in line with pregnancy, such as spending more time in her den, body licking and cradling objects. The inside of the habitat has been closed to the public.
Giant pandas are one of the world's most endangered species and have a very low reproductive rate, particularly in captivity. Their natural home is in a few mountain ranges in central China. There are about 1,600 giant pandas known to be living in the wild and some 300 in captivity, mostly in China.
(Reporting by Ian Simpson; Editing by Sandra Maler)