210. Birds, Bees And Educated Fleas!
OK well maybe not quite but it is incredibly common for mammals to eat their afterbirth, in fact apart from Humans, some marine mammals and some domesticated pets you could say that ALL mammals do.
It is hard to say, but these animals are going on instinct. Something built in that tells them this is what they should do, and who knows maybe a long time ago it was more common among humans too.
It may seem like a weak argument, but if you think about it the majority of mammals also carry and nurse their young in much the same way as we do so maybe we should take a cue from them on this and reach for the frying pan!