How do I look?: Morris watching

Provided I'm washed and shaved, that's all that really matters to me about my appearance. My wife can't get me to buy new clothes - she has to fight to get me to go to a clothing shop. I spend more money on old books. It dates back to when I became a scientist. You just begin to dress like a boffin. If you want to find the least colourful, least imaginative clothes, go into any laboratory. The point is, a scientist isn't interested in himself, he's interested in what is happening in front of him in his experiments, in his observations. Look at Bill Gates. If I didn't know who he was and I met him, I'd think he'd come to repair my computer, not that he ran the world's largest software firm. This is a very important change, historically: information about people's status in society is transmitted not by their clothing any more but by our knowledge of them through the media. Once, if you were a king, no one knew what you looked like, so you had to let them know how important you were through your personal appearance, your regalia.

I didn't used to be like this about my appearance. Back in the Forties and Fifties, before I became a zoologist, I was an artist. I caught the tail end of the surrealist movement and my clothing was very extravagant for the period, which was rather dour. In those days, I wore very bright clothes - like a red shirt with a yellow tie. When I met my wife I was having my first exhibition in London, with Miro, and I was dressed entirely in corduroy - corduroy trousers, corduroy jacket, corduroy shirt and a corduroy tie - and I remember it was very hot. I was in my Dali phase at the time and I was reading The Secret Life of Salvador Dali, which had just been published. Dressing in a strange way was part of our artistic rebellion.

I've never really looked youthful, and my hair's been like this since I was quite young. When I first appeared on television in 1956 they said to me, `Your hair's a disaster, you'll have to wear a toupee.' But I said to them, `I'm on live television with a chimpanzee and if you think I'm going to chase a chimpanzee around a studio trying to get back the toupee it's just taken off the top of my head, you're mistaken.' And then they said, `Your forehead's too big, we'll have to move your eyebrows up.' So I was sent to a make-up studio and they covered up my own eyebrows and put on a false pair. Finally I said, `This is ridiculous, I won't do it.' As far as I'm concerned, what I look like is not important, all that is important is that I convey to my television audiences my excitement and enthusiasm. I don't want to be given a lot of style, I want to be nondescript so that viewers concentrate on the subject, not on me. I have actually been thinking of having my hair shaved off for charity, I do get fed up with these wretched strands which I drag across my head, but I talked to a producer about it recently and he told me not to because it's become a kind of trademark.

I have never worn a ring in my life, or a bracelet or a medallion. I only wear a watch if I absolutely have to, if I'm going out and I'm going to leave my car on a parking meter. I like to have my arms and hands free of anything, it's a personal oddity that I have. I was watching the athletics the other night and almost all the sprinters had these little gold necklaces bouncing around on their necks - that would drive me mad. But although I don't wear anything, I am fascinated by things other people wear. What people don't realise is that virtually all jewellery started life as some sort of protective amulet. I've been collecting amulets and protective charms for years and I now have hundreds, like the Dream Catcher [pictured], which is used by American Indians to "catch" bad dreams.

I'm currently trying to lose weight. I always put on weight when I write, and I'm working on my third book this year - they were written back to back. Usually I manage to balance my life between my three worlds: painting in my studio, writing in my library and making television programmes. Working on location does keep you fit, because of the adrenaline and travelling. My weight has gone up and down on four occasions before. I can get it off, it's just a matter of eating less, which is a deprivation for me because I love food - for me it's an art form. I don't hold with all this nonsense about special diets, all you do is eat less and then you get thinner. At my age I'm less worried about looking overweight than about the health implications. When I was 40 I used actuaries' tables to work out when I would die and I calculated that it would be when I was 61. I'm 71 now, so I'm into extra time, and there's still so much I want to do and see.

`Body Guards: Protective Amulets and Charms', by Desmond Morris, is published by Element, price pounds 20