The pig is proverbial as a type of obstinacy and greed.
A pig is the emblem of St Anthony of Egypt (see also tantony pig).
pig in a poke something that is bought or accepted without knowing its value or seeing it first (a poke here is a bag).
Pig Latin an invented language formed by systematic distortion of a source language; a secret language formed from English by transferring the initial consonant or consonant cluster of each word to the end of the word and adding a vocalic syllable (usually -ay): so igpay atinlay.
squeal like a stuck pig squeal or yell loudly and shrilly; a stuck pig is one that is being butchered by having its throat cut.
See also piggy, pigs.