The natural world is endlessly fascinating. The clip above is from the first episode (Challenges of Life) of the new BBC series Life. You'll recognize the narrator.
I can't resist appending this quotation:
"For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much - the wheel, New York, wars and so on - whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man - for precisely the same reasons."You'll recognize the source.