Does the height matter? A bear could climb over it if it were 6' high or 11'-12' high. The electric fences are the 'primary barrier' and are what is/are keeping the bear(s) in. Occasionally (on mainland Europe) I have seen bears behind just the electric strands, with no mesh at all... In the UK, bears are currently kept behind some very basic barriers. Examples can be seen on the Whipsnade, Highland Wildlife Park and Yorkshire Wildlife Park galleries, for example. Usually (as in this picture) some kind of even lighter weight internal stand-off gives the fence a horizontal element, and prevents close contcat and digging with/against the main one.
