The usual thing, of course, is for such intense interests to take a back seat in adolescence, when even more compelling interests come to the fore. What is unusual is for them to come back to the front seat again, once the hormones have settled down. [ Yes, I realise there's an amusing front seat/back seat joke lurking here, but remember British adolescents never own or have access to cars]. Even more unusual is for there to be a living to made out of them: it is an enviably happy person whose life-work is of a piece with their childhood hobbies.
I remember, when my son was about nine and still deep in his own dinosaurs and natural history phase, going one Saturday afternoon to our local "real" camera shop, City Photographic, probably to buy my weekly supply of film. I gradually realised that he was rigid with focussed attention, like a pointer dog. Following his gaze, I saw a familiar face and haircut and heard a distinctive, rhotacized voice. It was Chris Packham, expert wildlife photographer, and one of the presenters of a favourite TV programme (and a much-watched "Dinosaur Special" video), The Really Wild Show. It turned out he is a local boy.
Now, Chris is a perfect example of what I'm talking about. He is one of that select band of wildlife presenters who are potential Attenborough heirs, and there is a reason for that: his enthusiasm and knowledge go all the way down. You won't find many TV celebrities who can talk about a childhood spent delving for snakes in heathy tussocks in the New Forest, then going to bed unwashed, in order to keep the (allegedly) delightful smell of grass snake on their hands. Or who know a certain woman who is an authority on slugs, who says the only way to distinguish certain species is to taste them. Such people are a precious resource.
Most of us fall by the wayside. I remember at university meeting a guy who was studying life sciences, and discovering we had a childhood enthusiasm for moths in common. It turned out that very night he was going to be running a mercury vapour trap in his college garden -- something I'd often read about but never done -- and he invited me along. It could have been the start of a beautiful friendship, and a revival of entomological passion.
But later on some other friends invited me to the bar, one thing led to another, and I forgot all about the light trap. So it goes. As in politics and all fields of endeavour, the crucial distinction in life is between those who express an interest, and those who show up.
Mariposas Nocturnas. Edith in Panama (2006)