Somewhere in this thread someone (Hal?) said something like  "grass does
not want to be eaten".  Yet insofar as horse are concerned, this is an
effective method of seed distribution.  The principal food supply for 19th
century urban populations of english sparrows, at least the the United
States, was undigested hay seeds in horse manure.  Is it perhaps possible
that gluten evolved as an agent to speed transmission of proto-wheat seeds
through the consumer's gut, there by increasing the number of undigested
seeds and providing an reproductive edge over non-gluten bearing grains?

Wheat, however, has its origins in the Middle East, and the primary grass
eaters in that region would be not horses but ruminants such as sheep,
goats and the like.  As I am unfamiliar with the output of such critters,
here is my question--Is their digestive process so efficient as to preclude
the passing of undigested seeds?

Chidiock