I’m a little concerned about the humane society that told you this. A) because seriously, misinformation to adoptees is really bad, B) they apparently thought they were giving you a wild animal, and C) they either didn’t know or didn’t care that this would be highly illegal?
Most vets won’t even treat injured wildlife, at least in Canada, because you are not permitted to keep domestic wildlife (as opposed to exotic) for longer than 24 hours unless you are a wildlife custodian.
In Canada there is no federal legislation prohibiting the keeping of exotic species—if there’s no specific municipal bylaws against it you can absolutely keep a lion in your backyard. But keeping domestic wildlife is strictly prohibited by federal law.
Humane Societies should know this because they’re one of the main receivers of calls people have when they’re having problems with animals. People try to drop all sorts of bizarre creatures off and they have to know what to do when someone dumps a baby raccoon on them.