I think the most alarming animals I have encountered are really poisonous snakes.

Human beings, because we're so clever, have removed every single one of those population limiting factors... So nothing controls our increase in numbers except our own wish. Since I first started making television programs, the population of the world has increased three times. That's an extraordinary notion. Can it increase four times? Can it increase five times? The Earth is a finite size. So a point will eventually come when we run out of food, when we run out of space and when we will have destroyed most of the natural world. So ought we to do something about it before that happens?

The notion of ever more old people needing ever more young people, who will in turn grow old and need even more young people, and so on ad infinitum, is an obvious ecological Ponzi scheme.

An understanding of the natural world and what's in it is a source of not only a great curiosity but great fulfillment...

It's like saying that two and two equals four, but if you wish to believe it, it could also be five ... Evolution is not a theory; it is a fact, every bit as much as the historical fact that William the Conqueror landed in 1066.

People are not going to care about animal conservation unless they think that animals are worthwhile.

I'm against this huge globalisation on the basis of economic advantage.