2 days ago Public Radio ran a story about a new portable electric fence you can carry in your backpack for bear defense around your camp. They said the battery is about the size of a VCR tape casette and the fence looks like a badminton net. They said it is undergoing some tests but should be approved next year. They said some instruction is needed because they knew of a case where a bear cub dropped into the center of the fenced area from a tree. (Presumably he was still trapped inside the next day). It develops about 6000 volts. Not a nice thing to forget about when you go out for a potty break..