Er Shun, panda on loan to Toronto Zoo, is pregnant

Er Shun, the giant female panda bear on loan to the Toronto Zoo from China as part of a breeding program, ispregnant with two cubs,andthe father could be any one of three pandas.

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The zoo announced that a fetal heartbeat was detected when Er Shun underwent an ultrasound on Friday. A second ultrasound performed Tuesday brought more good news when a second fetus was detected.

Dr. Gabriela Mastromonaco, the zoo's curatorof reproductive programs and research,told CBC News that confirmation of Er Shun's pregnancy was met with "a lot of singing and dancing."

"We just couldn't believe that we not only got her pregnant, but she had ovulated twice and had thetwins."

The zoo posted this video of the ultrasound images on YouTube. You can also watch the video by clicking on the image at the bottom of this story

Er Shun underwent two artificial insemination procedures in May: one usedsperm from Da Maothe male who came to Toronto from China with Er Shun in March2013 the second usedfrozen sperm from two giant pandas in China.

The gestation period for pandas is anywhere from 87 to 186 days.Breeding pandas is a difficult process.Female giant pandas are only receptive to breeding once a year for a period of 24 to 72 hours.

Zoo staff expressed cautious optimism about the news on Wednesday.

"While this is a positive sign, the followingthree to fourweeks are very critical," said a release issued by the zoo today. "Toronto Zoo staff are cautiously hopeful forhealthy births."

Assuming everything goes well, Er Shun's cubs will arrivein mid-October. An intensive care unit equipped with incubators has already been set up in the zoo's panda house to care for the cubs.

Zoo spokeswoman Jennifer Traceysaid the pregnancy is important news because giant pandas are an endangered species. Only about 3,000 are left;only about1,600 of those are in the wild.

DaMao and Er Shunarrived in Toronto amid much fanfare. They were greetedat the airport by Prime Minister Stephen Harper and his wife,Laureen.

The pandas will be at the Toronto Zoo until 2018, when they'll move to the Calgary Zoo forfive years.