Is this why the cave men call money 'clams' in the comic BC?

Question

http://news.yahoo.com/s/livescience/20080828/sc_livescience/giantclamsfedearlyhumans

Just saw this article "Giant Clams Fed Early Humans." At first I thought the clams were offering charity meals, but I think this may be the origin of clam-based currency.

Answer 1

Yes, because the first forms of money, represented i.o.u.'s for food...

The oldest coin ever found, has a picture of wheat engraved on it!