Rhino-mounted Bantu shock troops could have overthrown the Roman Empire. It never happened.

Forced to choose between limiting population or trying to increase food production, we chose the latter and ended up with starvation, warfare, and tyranny.

All human societies go through fads in which they temporarily either adopt practices of little use or else abandon practices of considerable use.

Much of human history has consisted of unequal conflicts between the haves and the have-nots.

I'd rather spend my leisure time doing what some people call my work and I call my fun.

Eurasia ended up with the most domesticated animal species in part because it's the world's largest land mass and offered the most wild species to begin with.

But this was the only way of life that humans knew for their first 6m years on the planet. In giving it up over the past few thousand years, we have lost our vulnerability to disease and cold and wild animals, but we have also lost good ways to bring up children, look after old people, stave off diabetes and heart disease and understand the real dangers of everyday life.