Boards
How come birds are much fitter than men?
I mean if you think how many miles a lot of species migrate every year, is there any way that a human could realistically do that? I mean even if it was overland surely the sheer distance would be too much for humans.
So how come birds can travel so far even though they're smaller? Has civilisation made us massively unfit or weren't we a hugely energetic species in the first place?