The Toronto Zoo’s polar bear, Aurora, gave birth to three cubs last week, but only one survived and is now in the Wildlife Health Centre’s intensive care unit.

On Nov. 11, the zoo’s staff noticed that the surviving cub was not moving strongly. A veterinarian soon moved the cub to WHC where they have been monitoring his temperature, taking blood samples and feeding him a special formula, said a press release from the zoo.

“This is an extremely critical time for this young cub and Zoo staff are providing 24/7 care to give him the best chance for survival as the first three months are crucial,” said Simon Hollamby, Toronto Zoo Veterinarian.

Eric Cole, Wildlife Care’s Acting Manager, said that Aurora, the mother bear, had “perfect maternal instincts,” after attempting to nurse each of the cubs after birth.

Mother polar bears typically give birth at the end of November or December, and emerge with their cubs in the spring, according to the press release.