I think I've known this for years. When I was a kid I had a book entitled "How things work". In it was a large picture, spread across 2 pages, showing birds, la

I think I've known this for years. When I was a kid I had a book entitled "How things work". In it was a large picture, spread across 2 pages, showing birds, land animals, people in cars, trains, aeroplanes etc, all moving from left to right as if in a race. Above each participant was a figure indicating something like Joules per gram. The "participants" in the "race" were ranked according to this figure, with the front-runners having the lowest associated values. Waay out in front was a man on a bicycle. Add in the help of cumulative drag and sharing the load against the wind resistance, it makes sense.