Where did pig-nosed orcs come from?
I imagine the answer to this is on a forum somewhere but I can't think of anything less inviting than an rpg internet forum. I don't think anything to do with Tolkien's orcs would suggest a pig nose. I suppose it could be just a beastly addition to make them less human and easier to kill without guilt. I suppose it could have been added to try and make them distinct from the gajillion other humanoids. Or maybe it was just the whim of a particular artist.
At the Earth's Core which is an adaptation of Burroughs' first Pellucidar book. In that book the soldier race that serve the evil Mahar are the ape-like Sagoths. But in the movie they don't look like gorillas, they look like humanoids with pig-noses. I wonder if this movie might have been where pig-nosed orcs came from. The Sagoths in the movie act very orc-like: are war-like, brutal, speak a different language, and act on the initiative of a more powerful evil. Coming out in 1976 it pre-dates the Monster Manual and might have been early enough to influence some of the artistic depictions. I'm curious what other possible origins have been given for pig-nosed orcs.