When I watch a nature documentary I find myself wanting to learn, well... up until the point where the gazelle gets eaten alive by ravenous hyenas, then I shut it off and stick my head back in the sand, because I don't want to learn.
and yes, you can find youtube videos of the above thing, that stuff disturbed me for about a week. Don't do it.
Now, the only 'nature documentaries' I watch are on the disney channel featuring animal voice overs and comedy for all ages!