In ancient Greece a sow was an appropriate sacrifice to Demeter and had been her favorite animal since she had been the Great Goddess of archaic times.
In ancient Egypt the egyptians regarded swine unworthy as sacrifice, except for when the full moon shone upon the lands. That’s when they sacrificed pigs to the moon and the god Dionysus.
But hey, wasn’t Dionysus a Greek god? Yes… he was. …my source for this information is wikipedia…