In Switzerland, it is illegal to own just one guinea pig.
The country passed a law in 2008, making it illegal to own just one guinea pig at a time because a cavy (guinea pig,) being a social animal moves around in herds and can get awfully lonely if left without a companion. But this doesn’t explain why Swiss road tunnels are loaded with explosives so that they may be quickly closed in case of invasion. But that’s another story.
The Haus of Dcaligari 