they mostly eat all berries and plant leaves
A bramble.
Border grass has purple berries. Another name for it is Liriope muscari. Keep the berries away from children and pets.
Smilax herbacea L. is most likely what you are looking at, or something within the same Smilax family. The berries hang from a single stem in a tight cluster resembling a dimpled golf ball. The berries begin as green clusters and ripen to a dark purple or black in the fall.
Apples usually they don't eat much fruit
yes black bears are omnivores they are third level consumers they eat fish berries and more!
Without more information or a picture, it can be difficult to identify the tree. It could be a black cherry tree, elderberry tree, or even a black walnut tree. I recommend consulting a local plant expert or bringing a sample to a garden center for proper identification.
Buffalo berries
Yes, rabbits do eat berries.
Mountain berries
What kind of berries. Different berries have different sugar.
Dingle Berries