It's an odd topic, but a familiar one. I haven't thought about this in ages!
I was about to post a photo on flickr of crab for sale at Fisherman's Wharf. I wanted to verify the sex of the crab. They appeared to be all male, as they should be, but I'm always getting the description of the male and female abdomens confused so I just had to make sure.
In my search for crabbing issues and processes, I ended up at iheartbacon.com. I noticed a link off to the side titled Pig Milk, and clicked on it.
Eric & I had been wondering about pig milk (and cheese!) for quite some time before we ended up sharing our thoughts with some friends a few years ago. Pigs can get big, but not big like cows, and they have have a lot more teets. So it's harder to milk them and the yield just doesn't seem to be worth the work is what we all came up with but we never really got confirmation. The link at iheartbacon offered up some answers along similar lines.
But we'd gotten a different answer about 2 years ago from a friend of a friend. He sent us the translation, as the original answer was in French. Apparently, man has only milked and produced milk by-products from herbivorous animals, including yaks, water buffalo, camels, horses, goats, sheep and of course, cows. The pig is omnivorous, as are most people.
Could you imagine human milk or cheese for sale?
Anyway, we've since lost the original email and have forgotten the reasoning behind the 'omnivore factor'. I think it may stem from old dietary laws? But I can't be sure. Eric just searched his old emails and did not find it. Perhaps, we'll have to send a follow-up email to our friend to refresh our memories.