The city is not a concrete jungle, it is a human zoo.

The idea that it is funny to see wild animals coerced into acting like clumsy humans, or thrilling to see powerful beasts reduced to cringing cowards by a whip-cracking trainer, is primitive and medieval. It stems from the old idea that we are superior to other species and have the right to hold dominion over them.

In a social environment that is ever crowded and impersonal, it is becoming increasingly important to reconsider the value of close personal relationships before we are driven to ask the forlorn question, 'Whatever happened to love?'

We are to put it mildly, in a mess, and there is a strong chance that we shall have exterminated ourselves by the end of the century. Our only consolation will be that as a species, we have had an exciting term of office.

We never stop investigating. We are never satisfied that we know enough to get by. Every question we answer leads on to another question. This has become the greatest survival trick of our species.

It must be stressed that there is nothing insulting about looking at people as animals. We are animals, after all. Homo sapiens is a species of primate, a biological phenomenon dominated by biological rules, like any other species. Human nature is no more than one particular kind of animal nature. Agreed, the human species is an extraordinary animal; but all other species are also extraordinary animals, each in their own way, and the scientific man-watcher can bring many fresh insights to the study of human affairs if he can retain this basic attitude of evolutionary humility.

Looking back now on the whole sexual scene we can see that our species has remained much more loyal to its basic biological urges than we might at first imagine. Its primate sexual system with carnivore modifications has survived all the fantastic technological advances remarkably well.