Most animals know humans are too much trouble to mess with.

Sure, you can kill one human. But next thing you know your whole species has gone extinct, or worse, has been domesticated into pocket yappy dogs that can't breathe properly.

In places where we've been around long enough staying away from humans has practically been bred into every surviving predator's instincts by now (which is what makes polar bears so terrifying, they're about the only dangerous predator that doesn't have this instinct yet, and probably never will, now that murdering whole species has become a bit of a bad look); anything that considered us prey and didn't learn not to simply doesn't exist anymore.

Wolves in particular (in the few places where they survive) definitely know not to mess with us, except maybe in the frozen depths of Canada, and so do most bears (again, with possible exceptions in the least populated bits of North America) except polar ones.