It's less fear and more about them doing calorie math. Bears won't waste the effort in most circumstances.

Depends on the bear. Black bears are known to be chickens.

Humans

Other bears and mooses maybe ?

Even if you’re the apex predator you try not to get hurt during the fight - an injury could mean death. this requires some form of sense for danger is my guess

and stating the obvious: fear of fire, heights etc

Math.

Dogs. A yearling like this would be, anyway.