In 1879, the Belgian city of Liege conducted a short-lived experiment using cats to deliver mail from the central post office to outlying villages. The letters were put into waterproof bags that were tied around the collars of 37 trained cats, but the animals proved slow and unreliable. Some took more than a day to reach their destination, while others simply didn’t bother. (From Ripley’s Believe It Or Not: Escape the Ordinary)