WASHINGTON, D.C. (WUSA) - Billie Jean, a 6-year-old Andean bear, could give birth to two cubs any day now, according to the National Zoo.
Veterinarians have examined Billie Jean weekly since Nov. 6, conducting ultrasounds that have revealed two "small distinct amniotic sacs" and "fetal growth and development," which could indicate that Billie Jean could give birth for the second time. She is the mother of Bernardo and Chaska, born in Jan. 2010.
Although hopes are high, and dedicated zoo-watchers are following Billie Jean's nesting activities via the Zoo's live webcam, veterinarians and Billie Jean's keepers are tempering their optimism with the reminder that Andean bears, like all bear species, can actually resorb one or both fetuses at any stage of the pregnancy--meaning Billie Jean could give birth to only one, or no cubs.
But the Zoo staff remains hopeful that Billie Jean will show her champion-caliber maternal instincts as she did nearly three years ago when Bernardo and Chaska arrived.
Newborn Andean bear cubsm weighing 10 to 18 ounces at birth, are practically bald, toothless and blind.
All of her cubs share the same father, Nikki, who was humanely euthanized in August after a yearlong battle with squamous cell carcinoma (cancer). Nikki and Billie Jean's natural breeding took place in April.
The Andean bear population in human care has experienced a lull in the past six years. If Billie Jean does give birth successfully, the cubs will be the only surviving Andean cubs in a North American Zoo since her first cubs were born.
And the last surviving Andean bear born in North America before that was Billie Jean herself.
Andean bears-also known as spectacled bears-are listed as vulnerable on the International Union for Conservation of Nature's Red List of Threatened Species, and it is estimated that there are only 2,000 left in their natural habitat.
During Billie Jean's denning period, Zoo visitors can see 2-year-old Chaska on exhibit near the lower entrance to American Trail, weather permitting.
To follow Billie Jean's progress, watch her on the Zoo's live webcam, read updates from the Zoo's Andean bear keepers and check for news on the Zoo's Twitter feed and Facebook page with the hashtag #cubwatch.