Rat Catchers, Madamba, Mozambique

While no longer a pression in developed countries, there are still rat-catchers in India and other developing countries.
Keeping the rat population under control was practiced in Europe to prevent the spread diseases to man, most notoriously the Black Plague and to prevent damage to food supplies.
Some rat-catchers in Europe would raise rats instead catching them in order to get more money from the towns. This, and the practice rat-fights, could have led to rat-breeding and the adoption the rat as a pet - the fancy rat.
A famous rat-catcher from Victorian England was Jack Black, who is known through Henry Mayhew's interview for London Labour and the London Poor.