Armies are a purely human invention. Most soldiers who go to war nowadays don't even do it because they're inherently aggressive.

Male chimpanzees have an extraordinarily strong drive for dominance. They're constantly jockeying for position.

The primate laugh is given in playful contexts, and as such has a strong similarity to the human laugh.

We start out postulating sharp boundaries, such as between humans and apes, or between apes and monkeys, but are in fact dealing with sand castles that lose much of their structure when the sea of knowledge washes over them. They turn into hills, leveled ever more, until we are back to where evolutionary theory always leads us: a gently sloping beach.

I've argued that many of what philosophers call moral sentiments can be seen in other species. In chimpanzees and other animals, you see examples of sympathy, empathy, reciprocity, a willingness to follow social rules. Dogs are a good example of a species that have and obey social rules; that's why we like them so much, even though they're large carnivores.

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?

Robin Hood had it right.Humanity's deepest wish is to spread the wealth.