If it makes any difference I once watched a spike
buck chase a bear from a food pile. Obviously the deer didn`t scare the bear, but he did pester him
until he left from what I believe was frustration.
The deer would snort loudly and jump back and this would cause the bear to run a short distance, survey the area and then cautiously sneak back in to eat apples. Then the process would start over.
I had no bear tag, and did not have permission to shoot bucks on the property I was on, so I simply enjoyed the show.
I would have no doubt that yotes could gang up and "pester" a bear away.