Penguins are, perhaps, the most loved of birds. We've been fascinated by them for just about as long as we've known they existed. When penguins are on land, their actions appear to us so humorous and expressive that we can be excused for thinking we understand them perfectly, identifying with what looks like moods and foibles similar to our own. Little do we realise that their private lives are as complex and mysterious as that of any wild animal or that the bulk of their existence - in terms of time, space and survival skills - takes place very far from our prying eyes, hidden beneath the ocean waves.