If everybody on the planet today had the same standard of living as the average European or American, we would need three new planets. But we don't even have one new planet. We have this one, and with the way we're polluting it, the shrinking water resources, the climate change, the experimentation with plants... the outlook is grim.

You can't do everything. You can't do health and forestry and agriculture. You've got to focus and do one or the other.

Anyone who tries to improve the lives of animals invariably comes in for criticism from those who believe such efforts are misplaced in a world of suffering humanity.

I believe the only hope for mankind lies in the hands of our young people.

The cheapest and most efficient way of slowing down global warming is to protect and restore the forests, particularly the tropical forests

It has actually been suggested that warfare may have been the principle evolutionary pressure that created the huge gap between the human brain and that of our closest living relatives, the anthropoid apes. Whole groups of hominids with inferior brains could not win wars and were therefore exterminated.

It's the bond between mother and child, which is really for us and for chimps and other primates, the root of all the expressions of social behavior.