A variety of animals have been used to deliver mail over the years, from camels and dogs to horses and pigeons. But cats? According to a 19th century article in the New York Times, around 1877 the Belgian Society for the Elevation of the Domestic Cat tested 37 cats for the task by taking them far from the city of Liege where they "promptly proceeded to 'scat.'" Within 24 hours, they had all returned home.
This result has greatly encouraged the society, and it is proposed to establish at an early day a regular system of cat communication between Liege and the neighboring villages. Messages are to be fastened in water-proof bags around the necks of the animals, and it is believed that, unless the criminal class of dogs undertakes to waylay and rob the mail-cats, the messages will be delivered with rapidity and safety.