One afternoon in the Arctic, a father polar bear and his polar bear son were sitting in the snow. The cub turned to his father and said: 'Dad, am I a hundred per cent polar bear?'

The father replied: 'Of course, son, you're a hundred per cent polar bear.'

A few minutes later, the cub turned to his father again and said: 'Dad, tell me the truth. I can take it. Am I a hundred per cent polar bear? No brown bear or black bear or grizzly bear?'

The father answered: 'Son, I'm a hundred per cent polar bear, your mother is 100 per cent polar bear, so you are definitely a hundred per cent polar bear.'

The cub seemed satisfied, but a few minutes later he turned to his father once more and said: 'Dad, don't think you're sparing my feelings. I've got to know. Am I a hundred per cent polar bear?'

The father was becoming distressed by the continual questioning and said: 'Why do you keep asking if you're a hundred per cent polar bear?'

The cub said: 'Because I'm freezing!'