Desmond Morris, 85
A zoologist, surrealist painter and writer, Morris (far right in picture) first appeared on our screens presenting the natural-history programme 'Zoo Time' in 1956. His 1967 book 'The Naked Ape' sold more than 10 million copies. He lives in Oxford
The BBC had a monopoly on TV until the winter of 1955. So when ITV started, the old guard there were horrified, and there was hostility between the two sides. David and I ended up presenting rival shows about animals; his, Zoo Quest, was on the BBC, mine, Zoo Time, was on ITV, and I was told, "Don't get in touch with him."
It was ridiculous, but the director of London Zoo arranged a meeting between the two of us and we finally met. We had the same sense of humour. I told him how the first programme I did had a bear cub called Nikki, who sank her teeth into my forearm and I bled for the first 30 minutes on live TV. And David had a similar story to tell me.
We soon discovered that it was not just animals we shared an interest in, but also tribal art, geology and fossils, and our families got to know one another over various dinners. The only big difference came in the 1960s, when I moved from animal behaviour to the human animal, and our career paths diverged.
When David took over as controller of BBC2 [in 1965], the first thing he asked me to do was a programme about animals. I ended up doing 100 episodes of Life in the Animal World. David was so good at the BBC that he was considered director-general material. But I know he was missing being out in the field. I remember him saying to me, "The boardroom is not my habitat, I'd rather be up to my knees in bat dung." Which is what happened.
I moved abroad to Malta for a few years in 1967 and David and his family often came to stay with us. He's not good holidaying; he can't relax in a pool like the rest of us. On one trip, I remember sitting on the sand in a small inlet with him, when these two children spotted a sea cucumber in the shallow water and exclaimed how horrid it was. David leapt to his feet, waded in, picked up the sea cucumber and proceeded to give them a 10-minute talk on how brilliant it was. It was clear to me then that there's nothing fake about him: everything he did was related to his sheer fascination of the natural world. And that comes across in his TV documentaries.
He's still doing it at the age of 87, which fills me with admiration. I think we both have that childlike schoolboy enthusiasm to want to find out everything about everything. As a boy, I wanted to get to 100 places in the world. I think I got to that a few years ago: I actually have a map on my wall with pins in all the places I've been to. David took a look at it once and I could see him thinking that if he had a map, it would be easier to put pins in the places he hadn't been.
David Attenborough, 87
Since joining the BBC full-time in 1952, Attenborough has become the country's premier wildlife documentary maker. His 'Life' series spanned nine parts and won too many awards to list. He lives in London
I started a nature series [in collaboration with London Zoo] on the BBC called Zoo Quest in 1954. It was just before ITV started, so I was surprised when I later heard that ITV had decided there was mileage to be got from another programme based around the zoo, under the directorship of a brilliant zoologist called Desmond Morris. My view was that we ought to meet, to see how we could exist together. But it was not the view of [then ITV broadcaster] Granada, and its chairman was insistent that we shouldn't meet.
But we did, through London Zoo's director, and we got on brilliantly. Desmond was a brilliant young scientist and polymath and he used his position as Curator of Mammals at the zoo to institute a regular seminar there on animal behaviour. Much to my pleasure, he invited me to join. After that we regularly met up, talking scientifically about the seminars, but personally as well; we laughed at the same things and we became good friends.
As a result of those animal-behaviour seminars, many of the ideas became incorporated in a book Desmond wrote, called The Naked Ape. It was a fantastic book – it still is – and it enjoyed worldwide success. For the first time someone was saying, "Abstract yourself and look at humans as a species in the same way you look at other species." It was a revolutionary thing to do and a lot of people thought it was demeaning to humans. After the success of the book, Desmond left the zoo and bought a villa in Malta in 1967, to write.
As a family, we used to go off and spend holidays with him. We spent lots of happy times looking for fossil shark teeth. They're beautiful things, up to three inches long, and there are many of them in Malta. As a family we'd get competitive with Desmond's about which of us would find the most, though now of course it's illegal to collect them at all.
Desmond was always more involved in the scientific world than I was, and he's more creative in his curiosity than I am, too: I'm much more of an observer. He does things with his observations scientifically, leading to books such as The Biology of Art. He's a wonderful painter, too, and he's given me two of his beautiful "Biomorph" paintings, of creatures unlike anything on Earth: they have this surreal, Dali-esque quality to them.
Desmond may have given me an insight into human behaviour, but he's given me lots of laughs, too. We think the same things are funny, and he's a brilliant raconteur. And it's always exciting visiting him in Oxford.
We both love collecting things and when I visited him a few months ago, I wanted to take a look at the beautiful crystals and minerals he's assembling right now: we enjoy showing one another what we have; there's even a joke rivalry to it.
'The Artistic Ape: Three Million Years of Art', by Desmond Morris (£30, Red Lemon Press), is out on Thursday