I can't believe that people are saying that they could care less about rats. The things are incredibly destructive and disgusting. You might change your tune if they infested your home.
Who cares about the rhetoric of what constitutes "rat free", the fact remains that Alberta has had a rat control program since the 50s and I for one have never seen a rat here. And I hope I never do.
This is Alberta's rat policy http://www1.agric.gov.ab.ca/$departm.../all/agdex3441
Some of the high lites being...
It's illegal to own rats as pets in Alberta.
The Norway rat does not live in the wild and needs to live by people to survive.
They can't make it through the mountains so they mainly come from Saskatchewan.
There was a rat scare a few years back in Acadia I think where rats were found and trapped. They figured someone was keeping them illegally and released them for whatever reason.
So yeah when they are found here it's news worthy.