Alberta has no rats
Since the '50s, Alberta has engaged in a deliberate effort to prevent rats from entering the province.History of rat control in Alberta. Government of Alberta. (2021-11-26). The municipalities along the Saskatchewan border maintain a "Rat Control Zone" in which all rat-friendly structures are regularly inspected.Extinction Agenda: How Border Patrols Enforce a Uniquely Rat-Free Alberta. 99% Invisible. Kurt Kohlstedt (2020-08-09).
The rat-free status of Alberta led to a Wikipedia edit war over whether the province should appear on a map of the brown rat's habitat. At some point it was decided to remove the map entirely from the English-language entry for Rattus norvegicus, but its presence on other Wikimedia projects means the edit war still rages on to this day.