Sir David Attenborough has told how the only regret of his career would be how much time he spent away from his family.
The much-loved TV nature expert, 91, said his work would often take him away from home for months at a time when his two children, Susan and Robert, were growing up.
He told broadcaster Louis Theroux: "I really shouldn't regret anything, because I've been just so unbelievably lucky.
"But if I do have regrets, it is that when my children were as young as your children, I was away for three months at a time.
"If you have a child of six or eight and you miss three months of his or her life, it's irreplaceable; you miss something."
Praising his former wife, Jane, for being so "understanding" during his earlier years, he added: "Perhaps you can't have your cake and eat it."
During the Radio Times interview, he also spoke of his fears over the effects of global warming, his gradual turn to vegetarianism and his secret weakness for chocolate.
After a career that now spans almost 60 years, he said he still feels incredibly lucky to be offered the opportunity to work on projects abroad.
He is currently presenting the fourth series of his show Natural Curiosities on W and in Sunday's first episode introduced viewers to the "pizzly bear" - a hybrid between a polar and grizzly bear.
Explaining that the line between the classification of species is more "fuzzy" than we tend to realise, he also said that gender differences in humans are less "clear-cut" than in the animal kingdom.
Asked whether he believed that men are naturally dominant, he said: "Anything that oversimplifies in that way is rather dangerous, because life is more complicated than that.
"There is a basis of that, but we now know that sexuality is not as clear-cut as you might have thought... these man-animal comparisons can be manipulated and distorted into what people want it to say, but biologically it's irresponsible."
A month after celebrating his latest birthday, Sir David added that he thinks about his own mortality "all the time", because: "It's more and more likely that I'm going to die tomorrow."
Asked if he expects anything to happen afterwards, he said simply: "No."
:: Read the full interview in Radio Times, out on Tuesday.