I sometimes try to imagine what would have happened if we’d known the bonobo first and the chimpanzee only later—or not at all. The discussion about human evolution might not revolve as much around violence, warfare and male dominance, but rather around sexuality, empathy, caring and cooperation. What a different intellectual landscape we would occupy!

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.

Perhaps it's just me, but I am wary of any persons whose belief system is the only thing standing between them and repulsive behavior.

I am personally not against keeping animals at zoos, as they serve a huge educational purpose, but treating them well and with respect seems the least we could do, and with 'we' I mean not just zoo staff, but most certainly also the public.

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".

It is well known that apes in the wild offer spontaneous assistance to each other, defending against leopards, say, or consoling distressed companions with tender embraces.

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