Alberta is marking a milestone that few jurisdictions on the planet can claim: 75 consecutive years without a breeding population of rats. 

Alberta's Rat Control Program launched in 1950 after the province first declared the Norway rat a pest when the rodents crossed the Saskatchewan border. The program was a way to keep the rats from spreading disease and damaging infrastructure and agriculture. Armed with new legislation, a dedicated "Rat Control Zone" stretching 600 kilometres along Alberta's eastern edge, and a network of municipal pest inspectors, the province halted the rats' advance within three years. 

"It's something that's been decades of work," says Alberta Ag Minister RJ Sigurdson. "It's not a task we take lightly."