Er Shun and the cubs are now under constant observation by giant panda experts from Chengdu Research Base of Giant Panda Breeding in China, as the next several hours and days are critical to their survival.

"We are so proud to be contributing to the ongoing survival of this endangered species," said John Tracogna, Toronto Zoo's chief executive officer, said in the press release on Oct 13.

For the next several months, the cubs will remain in the maternity area of the giant panda house, which is not open to the public. But zoo staff said they will try to provide regular updates on their progress.