Although it may sound complicated and expensive, electric fencing is actually a relatively simple and cost-effective way to secure bear attractants that cannot be removed or otherwise contained. Electric fences are easily adapted to a variety of situations – beehives, fruit orchards, hunting and backpacking camps, grain sheds, livestock enclosures, landfills, even high-use visitor areas and campgrounds – and are relatively easy to maintain and economical to build.
They can be installed permanently or temporarily. Large, permanent attractants like landfills or attractants will require a suitably substantial, permanent fence. On the other hand, hunters or backpackers will want to choose a very portable, lightweight version when heading into the backcountry. Long-term camps and hunting camps, which tend to harbour game meat, skins and trophy heads, should definitely consider electric fences to deter curious bears. An electric fence can also make even the most fearful ursophobe comfortable at night.
Electric fences deter bears by providing an electric shock when the animal touches the charged wires. Under normal operating conditions, an electric fence functions as an incomplete (open) circuit with repeating pulses of electricity generated by the energizer sent through the charged wires of the fence. When an animal touches a charged wire, it grounds the fence, creating a closed circuit. An electrical pulse travels through the animal and back to the energizer, delivering a shock to the animal.
Electricity, unlike gun powder-propelled lead, is a relatively benign form of deterrent. While the electric shock is unpleasant to animals (and humans, too), it is not lethal or even harmful. An electric fence is humane, since it can only shock the animal if it persists in making contact; once the animal moves away, the displeasure stops. However, if an animal gets caught in a fence for an extended period, it may die of stress, so periodic patrols of the fence are recommended.
Other objects and materials including vegetation, sticks, fallen trees and non-insulated posts that contact charged wires can also create a partial or total closed circuit. This partial or closed circuit can result in a reduced electrical charge (voltage) and an inadequate shock to repel bears that contact the charged wires. For these reasons, fences should be checked and maintained regularly to address this potential problem. Download our maintenance check list.
One of the benefits of electric fencing is that it not only deters bears, but it teaches them to keep away. Bears are intelligent creatures. After a few visits to a potential food source and receiving nothing but a painful electric shock, they will learn to avoid the fence (and thus the attractant) and may even leave the area for good.
A biologist in Minnesota reported good success deterring bears from repeated attacks on beehives by using a temporary prefabricated fence with a charger powered only by D-cell flashlight batteries. The key in this instance was liberally applying foil strips smeared with peanut butter and honey to the hot wires about 20 to 24 inches (50 to 60 cm) above ground, about head height for the bears. The strips would be torn off by morning, but the bears respected the jolt they received and did not break down the fence. Solar charged units are also available.
Researchers also have adapted portable fence units to other items they want bears to stay away from. For example, the “electric lunchbox” is a small picnic cooler that has been fitted with an apparatus adapted from a portable electric fence unit that gives the bear a shock when it tries to remove the bait. In initial tests, the electric lunchbox has caused black bears to run from the area and avoid the cooler when they returned. Chicken coups and even regular livestock fences have been successfully hot-wired to deter bears.
For more information on how to design and build an electric fence to meet your needs, the Living with Wildlife Foundation has prepared an excellent Electric Fencing Guide, which covers a variety of applications, from landfills to backcountry camps. Click here to download instructions for setting up a portable electric fence. Click here to download instructions for electrifying a cooler or garbage can.
While it may seem counterintuitive, it’s a good idea to train bears to avoid your electric fence after it’s installed. Apply a smell to the electric fence to attract the bear’s nose. This can be done by putting food grease on a sponge and keeping a fresh coat on the wires. Bears, when they encounter a new smell will test it with their tongues tranfering the smell to their vomeronasal orgain papilla behind their incisors. Once they are zapped they will have little interest in what is being protected. Otherwise bears are like sheep and their dense fur can insulate them from being shocked by an electric fence.
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May Safely Graze – Protecting Livestock Against Predators by Eugene L. Fytche
For a copy of the book, contact Eugene at 613-256-1798 or R.R.#1 Almonte, Ontario K0A 1A0
Recreation Tech Tips from US Forest Service, Specifications for Portable Electric Fence Systems as Potential Alternative Methods for Food Storage: click here.