Under the right conditions, electric bear fences can be a great tool for campers, backpackers, kayakers or hunters. They are also good for keeping bears away from bee hives, food caches, smoke houses and field camps. Wildlife biologist Tim Peltier was grateful for his fence the day he heard a "pop" while he was cooking dinner at his campsite and turned around to see a bear running away. He hadn't heard the bear sneaking into the campsite from behind him, attracted by the food smells [source: Woodford].
Engineers first developed electric bear fences in the 1930s. The first bear fences were cumbersome to move, but modern versions are much more portable; some handy models fit easily into a backpack. One larger electric bear fence is powered by a 12-volt car battery and a solar charger, while some smaller fences weigh only a few pounds and use 2 D-cell batteries [source: Woodford].
Bear fences come with an energizer, fence poles, a grounding rod and connectors, fencing line, a volt meter and an alarm. They work by giving the bear a short, intense shock when it touches the fence [source: National Park Service]. The shock is not strong enough to hurt the bear, but bears, like people, don't like to be shocked. Researcher John Gookin says that, when a bear touches an electric bear fence, it "cries like a baby and runs away," and will stay away from the fence after that [source: Woodford]. A properly used electric bear fence is a good way to teach curious bears to stay away from your campsite.
To use a bear fence the right way, you need to set it up well. Clear all vegetation away from the bottom wire, and make sure the fence has a good ground -- you can check with the voltage meter to make sure. Remember to turn the fence on and shut the gate, and handle the equipment carefully to make sure you don't break any of the more delicate parts [source: National Park Service].
Conditions can affect how well an electric bear fence works. The ground wires work best in damp ground, and don't work well in sand or gravel. Rain and damp snow can interfere with the fence's effectiveness, and the fence works only as long as its batteries do [source: Woodford].
The National Park Service warns that electric bear fences are not foolproof. A bear that is being chased by another bear can easily break through the fence. They also warn that the fence is never a replacement for clean campsite maintenance and proper food handling, since a bear that is hungry enough might ignore the shock if the temptation is strong [source: National Park Service]. But using an electric bear fence along with good bear country etiquette is a great way to keep large, furry uninvited guests away from your campsite.
For more information on bear protection and other wilderness survival tips, follow the links on the next page.