Finding rats in the town dump is hardly cause for comment in most of the world. Rattus norvergicus (the Norway rat) has spread to all but a few bits of the planet, giving rise to the urban myth that city dwellers are never more than six feet away from a rodent.
However, the western Canadian province of Alberta has prided itself on being one of those rat-free bits for more than half a century. So when an infestation was discovered in early August outside Medicine Hat, a city of 72,000 people, it was headline news.
Pest-control officers installed high-definition cameras to track the rats, set up poisoned traps to catch them and released two bull snakes to kill those too wary to be trapped. The snakes, which look like rattlesnakes but are non-venomous constrictors, had been caught after citizens complained. They are normally released in a wilderness area when found in town, but in this case they were deployed to the dump.
Pictures of dead rats (those not disposed of by the snakes) seemed to signal early success. But as the corpses continued to pile up—there were 103 by August 27th—and rats were sighted in residential areas, the city opened a new front in the war: Operation Haystack. This involved stacking bales of hay stuffed with poison at 15 locations. Alison Redford, the provincial premier, promised the extermination effort would be “unrelenting.”