Black bears are the only bears found in the east.  They are smaller and less aggressive than the Grizzly but still can be 400 to 500 pounds.  Black bears have limited eyesight but a keen sense of smell and hearing. As we have encroached into their territory more and more, the incidences where bears have attacked humans has risen, however, it is still rare to be attacked by a black bear.

Many black bears know that packs contain food, and they are known to quickly snatch the food from an unguarded pack or to take food from a campsite.  For this reason, shelters in the Smokies have chain-link fencing to ward off the bears, and Shenandoah National Park has steel poles with prongs at the top for hikers to lift packs high off the ground.  If there are no bear barriers or poles to hang your pack, then be sure to set up your own contraption to hang your food sack from a tree.  Not only will this prevent unwanted bears from encroaching in your area, it will also keep your food safe from other critters.

Do not approach a bear if you see it, but do keep an eye on its behavior.  Like any other wild animal, noticing a change in behvior, whether it stops feeding, begins to watch you, changes its path, etc... signals that you are too close.  Proximity to the bear may provoke aggressive behavior, thus back away slowly, increasing the distance between you and the bear, while watching the bear at the same time.  The bear most likely will do the same.  However, if the bear continues to approach you without vocalizing or swatting, try to change your direction.  If that doesn't ward off the bear, stand your ground.  Now if the bear gets closer, shout at it, act aggressively and try to intimidate the bear, making you and your group seem as large as possible.  Throw rocks and use what you have to ward it off.  It is not recommended that you run, turn away, or leave food for the bear at this point.  (advice from http://www.nps.gov/grsm/naturescience/black-bears.htm)