Humans are, along with other primates, the only animals to wipe their bottoms after defecating. However, the human habit of sitting upright, whether in the communal latrines of ancient Rome or the Elizabethan water-closet of John Harrington (the spiritual father of the modern loo), means there is a lot more wiping to do. Richard Smyth provides the definitive history of how we have wiped over the centuries.