Many ingame quests actually mention mobs that feed off lalafells
This one FATE-enemy (can't remember it's name, 30ish lvl fate, dragon(ish)) had lalafells listed as it's favourite food.
Man I got angry and tried to solo that with my lalafell - only to end up as fodder for the monster. One day I'm going to find that genocider and get my revenge for all the lalafells he has eaten.

And no, I don't think Lalafells have been eaten by Miqo'tes, if anything it's the other way around. I imagine it being somewhat similar to old Tarzan-movies in which a group of pygmies dance in a circle around a cooking pot...