I don't do endurance rides so cannot speak from the perspective.

I only ever take water whether training or racing or commuting (2-3hours max).

My partner and eldest son do a 90-170km training ride every Sunday, so they are several hours "on the bike". They take one bottle of plain water and one bottle with plain glucose dissolved in it. They top up the plain water at when the bunch stops to wait for everyone at schools. If they know it will be over 100km they will take Leppin's with them. (They always take a handful of muesli bars, although they often come home uneaten)

As for lemmings, I guess well squeezed and filtered they might just work - don't want that fur stuck in the back of your throat like a crusty bike bar though!