That feeling when you're so cold you'd give anything to be warm - I've had it before, literally huddled around a candle flame on an ice sheet.

You're not human if you don't feel fear. But I've learnt to treat fear as an emotion that sharpens me. It's there to give me that edge for what I have to do.

I've eaten sheep's eyes, the still hot meat from a zebra killed by a lion, and maggots which give you 70 calories to the ounce.

Survival can be summed up in three words - never give up. That's the heart of it really. Just keep trying.

I do see a lot of the hard end of ecology, and my feeling is that we live on a super-exciting planet but a super-fragile one.

I've had so many injuries in my life that it's ridiculous.