09/30/2015 09:04 EDT | Updated 09/30/2016 05:12 EDT

Toronto Zoo's Giant Panda Er Shun Is Pregnant With Two Cubs

Giant panda Er Shun's ultrasound showed two fetal heartbeats.

TORONTO — A giant panda at the Toronto Zoo is pregnant.

The zoo says Er Shun, one of two giant pandas on loan from China, is pregnant with two fetuses.

They say the panda underwent two non-surgical insemination procedures on May 14 and sperm was used from the other panda in Toronto, Da Mao, plus sperm from two other giant pandas based in China.

The zoo says a veterinarian detected a heartbeat on an ultrasound conducted last Friday and discovered the beating heart of a second fetus on Tuesday.

On May 14, giant panda Er Shun underwent two non-surgical artificial insemination procedures as part of the Giant Panda...

Posted by The Toronto Zoo on Wednesday, September 30, 2015

The zoo expects the babies will be born in the next three to four weeks.

They are "cautiously hopeful" and the coming weeks are critical. 

Er Shun and Da Mao arrived from China in 2013.

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