Attenborough is gravely concerned about the effect humans are having
The highly respected wildlife presenter Sir David Attenborough is celebrating 50 years in broadcasting, and has spoken to the BBC World Service's Outlook programme about his career.
Sir David, who has worked on more than 500 natural history programmes and won countless awards, started his interest in wildlife early.
"As a small boy I lived in Leicestershire, where there are fossils from 150 million years ago, and they were beautiful and mysterious," he said.
"When you know how it got there, you know that yours are the first eyes to see it, and it's thrilling - I still feel the same."
Sir David joined BBC television after being turned down by radio, and began full-time presenting on the successful Zoo Quest programme.
You have to learn what you can put into the hotel bath safely
"London Zoo in those days sent out expeditions to collect animals - you don't do that now, but you did then - and I thought if we went, we could go with a camera and show the man from the zoo jumping on a python," Sir David explained.
"Then when we came back we could show him live in the studio with the python - but then on the first programme he became very ill.
"Because the programme was live, the producer said 'if he can't do it, the only person who can do it is you'."
It was at this point that Sir David began learning some of the secrets of working with animals.
"You have to learn what you can put into the hotel bath safely," he said.
"Snakes of course you have to be careful of because if the hotel room is properly warm they get rather lively."
His encounters with gorillas are part of TV history
Understanding some of these secrets of animal behaviour has helped him produce 250 natural history programmes, as well as narrating a further 250.
"You've got to know about animal etiquette, but it's particularly so in primates," he explained.
"You have to let them know that you're there - you have to sit in a prominent place so that they can see you.
"As you get closer to them, you have to give tiny little belches as you go along so that they know where you are."
But in one famous sequence involving a female gorilla, things did not go according to plan.
"I knew she was close but I didn't know quite where she was.
Understanding the natural world and how it works is one of the deep abiding pleasures of life
"She looked at me and I looked at her. Then she looked at me in a slightly ruminative way and put forward a hand like an enormous black boxing glove and put it on top of my head."
Sir David was forced to spend hours with the gorilla to avoid giving offence.
After she finally left, he was told by his producer that he had not got the footage required - and had to go back to reshoot.
His enthusiasm is one of the key factors in the success of his programmes, something he acknowledged openly.
"Understanding the natural world and how it works is one of the deep abiding pleasures of life as far as I'm concerned - and I believe that viewers think that too."
And he said that meant not over-sentimentalising certain aspects of nature.
"If you saw the reality of a lion hunt it would be very, very easy to make people nauseated by it - you sit comfortably by your fireside and that sort of sight is plainly unpleasant," he said.
Sir David's programmes are seen by millions of people
"On the other hand if you sanitised it and cut it out, you are grossly distorting the character."
One letter which said the money spent on sending Sir David and his camera crew to film a lion hunt - something the viewer termed "disgusting" would be better spent on training lions to eat grass.
In fact Sir David has long been highlighting in his programmes the damage that human beings are doing to the planet - every series ends with a comment on this nature.
"I think that the population of the world is much, much more aware of what is happening to the planet than it was 50 years ago," Sir David said.
"It's a very good thing that that is so, because in fact what we've been doing to the planet over the last 50 years has also increased in severity."