I think it's naive to think any large urban metro can be rat free. As long as you have items shipped in from other areas you will be getting the pests from those areas as well.
https://globalnews.ca/news/4342316/r...-free-alberta/
3 rats found this spring in Calagary, The Horror!
Looks like rat control is a huge beusiness in a province that claims to be rat free. Check out this website, it reads like a SciFi novel.
https://spartanpestcontrol.com/calga...estation-rise/
"INTERESTING FACTS ABOUT RATS
1. Survive a five-story fall without injury
2. Last without water longer than a camel
3. Survive large doses of radiation
4. Survive being flushed down the toilet (and find their way back inside via the same route)
5. Swim for half a mile in open water
6. Build immunity to poison
7. Eat their own feces for nutrients"
"TURNING INTO ZOMBIE RATS"
"SOME RATS CAN GROW UP TO BE ALMOST 9 POUNDS"
I don't know how Alberta can claim to be rat free when they seem to have plenty of rat pest control companies.
In Toronto they can be found in most alley ways, I've seen a large one inside The Black Bull on Queen street that was the size of a small cat. It ran from one end of the bar to the other during the day and sent people running and screaming.