She must get her cub to the sea-ice before it breaks up and thaws, otherwise, they will be trapped on the island for the summer with little to eat.

 

She needs to be careful. Males roam in ice fields below. And they kill cubs. They will try to mate with their mother, so she has their cubs instead. But the larger males find deep snow and steep slope heavy-going. She wisely keeps her cub to the higher ground.

 

Back at the den sites, other cubs are yet to emerge. They appear over a five-week period from March to April. After ten days of waiting, something stirs. The mother has waited six whole months for this moment.