This really is pretty pottery, from the Beaker People (much, much later than the N’s) used in the other topic I posted tonight:
http://cosmos-images1.imgix.net/file/spina/photo/18539/190404-pots-full.jpg
Cannibalism isnt that old a practice. Read a little about the Japanese in WWII. Fly Boys by James Bradley might bring it to the latter days.