Video grab from the incredible footage of a 12-day-old polar bear cub and its mother at Berlin Zoo, shot using cutting edge camera technology.See National News story NNpolar .A polar bear cub the size of a guinea pig looks to be dreaming of a white Christmas in adorable secret footage.The 12-day-old cub spends most of the day snuggled up to mum in a nesting cave that even zookeepers aren't allowed in.But new camera technology at the Berlin Zoo means everyone can follow the newborn's development in the cosy den from afar.The cub's eyes and ears will open when it is around 30-days-old but for it now relies on mum Tonja to keep warm and safe.