The intuitive connection children feel with animals can be a tremendous source of joy. The unconditional love received from pets, and the lack of artifice in the relationship, contrast sharply with the much trickier dealings with members of their own species.

If you want to design a successful human society you need to know what kind of animal we are. Are we a social animal or a selfish animal? Do we respond better when we're solitary or living in a group?

The evolutionary struggle for survival is really a self-serving series of blows and stabs, and yet it can lead to extremely social animals like dolphins, wolves or, for that matter, primates.

Morality, after all, has nothing to do with selflessness. On the contrary, self-interest is precisely the basis of the categorical imperative.

There is little evidence that other animals judge the appropriateness of actions that do not directly affect themselves.

If both parties have a stake in the other, the chances of them killing each other are going to be reduced.

Females avoid conflict. They are afraid of violence. The males, on the other hand, are less averse to strife. But once conflict breaks out, the males are much better at reconciling. In a study done in Finland, children who had quarreled were asked how much longer they intended to be angry at one another. The boys proudly said: "Oh, at least one or two days." The girls said "forever".