Living on the bodies of mammals, oxpeckers manage to get quite a varied diet. A maggot here, a tick there, a little sip of blood, perhaps a little ta… - David Attenborough

Immensely powerful though we are today, it's equally clear that we're going to be even more powerful tomorrow. And what's more there will be greater compulsion upon us to use our power as the number of human beings on Earth increases still further. Clearly we could devastate the world. […] As far as we know, the Earth is the only place in the universe where there is life. Its continued survival now rests in our hands.

This is the last programme in this natural history, and it's very different from all the others because it's been devoted to just one animal: ourselves. And that may have been a very misleading thing to have done. It may have given the impression that somehow man was the ultimate triumph of evolution, that all those thousands of millions of years of development had no purpose other than to put man on Earth. There is no scientific evidence whatsoever for such a belief. No reason to suppose that man's stay on Earth should be any longer than that of the dinosaurs. He may have learned how to control his environment, how to pass on information from one generation to another, but the very forces of evolution that brought him into existence here on these African plains are still at work elsewhere in the world, and if man were to disappear, for whatever reason, there is doubtless somewhere some small, unobtrusive creature that would seize the opportunity and, with a spurt of evolution, take man's place. But although denying a special place in the world may be becomingly modest, the fact remains that man has an unprecedented control over the world and everything in it. And so, whether he likes it or not, what happens next is very largely up to him.

Each [pelican] has already survived many perils in its young life. As a chick, it fought battles with its brothers and sisters and won.