Scientists at the National Zoo say they have detected a rise in hormone levels in the female giant panda, Mei Xiang (may-SHONG) that could indicate she may give birth or end a false pregnancy by early July.
The zoo said Tuesday that the hormone rise isn't enough to know whether Mei Xiang is pregnant. Zoo veterinarians have been conducting ultrasounds twice weekly, but they have not yet detected a fetus.
Scientists say panda fetuses don't start developing until the final weeks of gestation.
A Chinese panda breeding expert helped zoo scientists artificially inseminate Mei Xiang in January. She and panda Tian Tian (tee-YEN tee-YEN) had attempted to mate but weren't successful.
Their only cub, Tai Shan (tie-SHON), was born July 9, 2005.