Have there been vegans claiming that veganism is natural, and that this is somehow a reason to be vegan? Because that would be dumb. Veganism is an ethical stance, after all, so I'm not sure on what basis that argument would even rest.<p>Also, archaeologists who don't know about nutrition should probably not talk about nutrition as if they did. There are plenty of non-animal sources of B12, including soil (you know, where vegetables grow?).