Feeding bears (intentionally or unintentionally) trains them to approach homes and people for more food. Bears will defend themselves when people get too close so don’t risk your safety and theirs!
If black bears feel nervous, they may clack their teeth together (Sounds of a black bear huffing and popping), moan, blow, huff, or stomp the ground. A bear might stand up to get a better look at whatever is bothering them. If they are highly agitated and fearful, they may bluff charge (run toward you and then stop before reaching you).
These are all ways the bear is showing you it is uncomfortable with the situation and it wants you to give it some space. These are NOT indications of aggressive intent or that an attack is about to happen.
Truly predatory or aggressive black bears are extremely rare. But if you do encounter a bear that is approaching you quietly with intention, and it attacks you, FIGHT BACK!
Do not feed roadside, park or neighborhood bears! You may think that feeding a bear will encourage bears to appreciate you or other humans. But bears don’t see it that way.
A fed bear does learn something from getting fed. It learns to overcome its instinctive fear of humans. In essence, feeding bears “rewards” bears for approaching people in the same way a treat rewards a dog for coming on command.