Prepared by the National Wildlife Control Training Program. Research-based, wildlife control information.
- Explain key elements of bear biology that are important for their control.
- Effectively communicate the options for the control of bears.
- Describe how to avoid damage by bears.
- Identify the risks involved with controlling bears.
Black bears (Ursus americanus) may damage bird feeders, bee hives, and crops, as well as raid trash cans and dumps. On occasion, they will enter buildings and vehicles in search of food. If a bear has entered a structure, immediately contact your local police agency. Black bears may travel many miles in early summer seeking food and prior to breeding season. They may end up in suburban areas such as parks and school yards. If a bear is treed in an urban area, keep people and pets away, and let the bear leave on its own if possible. Darting and translocation of a bear is high risk for both the bear and agency staff.
Black bears are protected by federal and state laws and regulations throughout their range.
Black bears (Figure 1) are the smallest and most widely distributed of the 3 species of bears in North America. They are the only bear species in the northeast. Bears are massive, strong animals.
Black bears that live east of the Mississippi River are predominantly black, and some may have a light blaze on their chest. In the Rocky Mountains and westward, shades of brown, cinnamon, and blond are common. The head is moderately-sized with a straight profile and tapering nose. The ears are relatively small, rounded, and erect. The tail is short (3 to 6 inches) and inconspicuous. Each foot has five curved claws, about 1-inch long, that do not retract. Bears walk with a shuffling gait but can be quite agile and quick.
Health and Safety Concerns
Bears suffer from a variety of internal and external parasites, some of which may be transmitted to humans. Zoonotic diseases include the worm responsible for trichinellosis, and the protozoan that causes toxoplasmosis. Surveys have revealed that a small percentage of bears contract tularemia, brucellosis, and leptospirosis. Few bears have tested positive for rabies.
Although black bears generally avoid humans, they have attacked people. However, encounters are rarely fatal. Always respect bears and keep a safe distance. If a bear starts to approach, shout and wave your arms to try and scare the animal.
General Biology, Reproduction, and Behavior
Black bears become sexually mature at about 3½ years of age, but some females may not breed until their fourth year or later. Black bears breed during the summer, usually in late June or early July. Males travel extensively in search of receptive females, and mating individuals do not form pair bonds. Rival males may fight one another, and unreceptive females may fight with males. Females that are dominant may suppress breeding activities of females that are subordinate.
After mating, the fertilized egg does not implant immediately, but remains unattached in the uterus until fall. Females in good condition usually produce 2 or 3 cubs that weigh 7 to 12 ounces at birth. Bears in urban areas with subsidized food have had up to 5 cubs in a single litter.
Females give birth between late December and early February while they are in their dens. After giving birth, the sow may continue torpor (winter sleep) while the cubs are awake and nursing. Females that are lactating do not come into estrus, so females generally breed every other year. Only females care for young. Males sometimes kill and eat cubs.
Cubs are weaned in late summer, but usually stay close to their mother throughout their first year. After the breeding season, females and their yearlings may travel together for a few weeks. The cubs leave the mother when the female comes into her next estrus.
Sites for dens are quite variable and include piles of rocks or brush, excavations, hollow trees, and structures made by humans. The den floor may be covered with grass and leaves, or left bare. Many dens are at ground level under fallen trees, or sometimes even decks.
Black bears typically are nocturnal, although occasionally they are active during the day. In the South, black bears tend to be active year-round. In northern areas, black bears undergo a period of torpor during winter, which they spend in their dens. During torpor, individuals may remain in their dens for 5 to 7 months (late October to early April), foregoing food, water, and elimination.
The home range of a black bear depends on the type and quality of habitat, and the sex and age of the bear. In mountainous regions, bears encounter a variety of habitats by moving up or down in elevation. Where the terrain is flat, bears typically range more widely in search of resources. Most adult females have well-defined home ranges of 5 to 20 square miles. Ranges of adult males are several times larger.
Black bears frequent heavily forested areas, including large swamps and mountainous regions. Black bears depend on forests for food, water, cover, and space. Mixed-hardwood forests interspersed with streams and swamps are typical habitats for bears. Black bear populations have their highest growth rates in eastern deciduous forests, where there is a variety and abundance of foods, especially near urban areas.
Black bears are omnivorous and forage on a wide variety of plants and animals. Their diet typically is determined by the seasonal availability of food. About 80% of their diet is plant material, and typical foods include grasses, berries, nuts, tubers, inner bark, insects, small mammals, eggs, carrion, and garbage (Figure 2). Shortages of food occasionally occur in northern ranges when mast crops (berries and nuts) fail. At those times, bears travel more widely in search of food. Human encounters with bears are more frequent during such years, as are complaints of damage to crops and losses of livestock.
Voice, Sounds, Tracks, and Signs
Bears normally are silent when traveling. They emit grunts with young, and may blow and click their teeth if they are upset. Females use loud, staggered grunts to threaten unwanted males. Bears utter moans when subordinate to others.
Tracks of bears are recognized by their shape and size (Figure 3). The heel rarely shows in the track of a front foot. Front feet average 4½ inches in length and 4 inches in width. Rear feet are 7 x 3½ inches.
Scat of black bears varies in color and consistency, depending on diet. Well-formed scat averages 2½ inches in diameter, and 5 to 12 inches in length.
Damage to Landscapes
Bears can cause extensive damage to trees, especially in second-growth forests, by feeding on the inner bark, or clawing the bark to leave territorial markings. Black bears damage orchards by breaking trees and branches in attempts to reach fruit. They often will return to an orchard nightly. Due to repeated damage to orchards, and trees with broken limbs, losses often are economically significant.
Damage to Crops and Livestock
Black bears damage field crops such as corn, and occasionally alfalfa or oats. Large, localized areas of broken, smashed stalks show where bears have fed in cornfields. Bears eat the entire cob, whereas raccoons strip the ears from the stalks and chew the kernels from the ears. Black bears prefer corn in the milk stage.
Few black bears kill livestock but the behavior, once developed, usually persists. The severity of predation by black bears usually makes solving the problem urgent for those who suffer damage. If bears are suspected, check the carcass for deep tooth marks (about ½-inch in diameter) on the neck directly behind the ears. On large animals, look for large claw marks (½ inch between individual marks) on the shoulders and sides. After an animal is killed, a black bear typically will open the body cavity and remove the internal organs. A black bear will eat the liver and other vital organs first, followed by the hindquarters. Udders of lactating females are often consumed.
Predation by bears should be distinguished from attacks by coyotes or dogs. Coyotes typically attack the throat of their prey. Dogs chase their prey, often slashing the hind legs and mutilating the animal. Tooth marks on the back of the neck usually are not found on kills made by coyotes and dogs. Claw marks are also less prominent on kills by coyotes or dogs, if visible at all.
Livestock behave differently when attacked by bears. Sheep tend to bunch when they are approached, and 3 or more often will be killed in a small area. Cattle tend to scatter when a bear approaches. Bears usually kill a single animal. Hogs evade bears in the open, and are more often killed when they are confined. Horses rarely are killed by bears, but they do get clawed on the sides.
When a bear makes a kill, it usually returns to the site at dusk. Bears prefer to feed alone. If an animal is killed in the open, the bear may drag it into the woods or brush, and cover the remains with leaves, grass, soil, and forest debris. The bear will return periodically to the cache to feed on the decomposing carcass.
Black bears destroy beehives (Figure 4). Damage to beehives includes broken and scattered combs and hives, with claw and tooth marks. Hair, tracks, scat, and other sign may be found in the immediate area. A bear usually will use the same path to return every night until all of the brood, comb, and honey are eaten.
Damage to Structures
Black bears can damage homes and vehicles when searching for food. Black bears also will scavenge in garbage cans, break in and demolish the interiors of cabins, damage bird feeders, and raid campsites and food caches.
Damage Prevention and Control Methods
Prevention is the best approach to handling damage by black bears. Sanitation and proper management of garbage are essential. You should store food, organic waste, and other attractants in bear-proof containers. Use garbage cans for nonfood items only, and place food waste in bear-proof garbage receptacles (Figure 5). Pick up garbage regularly, and place garbage at the curb the morning of pick up rather than the night before. Reduce access to landfills through fencing, and bury refuse daily.
Eliminate garbage and carcass dumps. Surround dumpsters with electric fences. Only feed birds during winter, when bears are denning. Plant crops (e.g., corn, oats, fruit) away from forest edges if possible. Pick and remove all dropped fruit from orchards.
Prohibit all feeding of bears. If possible, locate campgrounds, campsites, and hiking trails in areas that are not frequented by bears. If feasible, clear hiking trails to provide a minimum viewing distance of 50 yards down the trail. Avoid bear feeding and denning areas.
Black bears can tear open doors, rip holes in siding, and break glass windows to gain access to food stored inside cabins, tents, and other structures. Use solid frame construction, ¾-inch plywood sheeting, and strong, tight-fitting shutters and doors. Steel plating is more impervious than wood.
Place beehives on a flat or low-sloping garage roof. Add extra roof braces as 2 hives full of honey can weigh 800 pounds or more. Another technique is to place hives on an 8- X 40-foot flatbed trailer, and surround it with a 3-strand electric fence. Though expensive, this method makes hives less vulnerable to bear damage and makes moving them very easy.
Confine livestock in buildings and pens at night, especially during lambing or calving seasons. Remove and dispose of carcasses by deep burial. Place livestock pens and beehives away from wooded areas or protective cover, and surround them with electric fences.
Fences have proven effective in deterring bears from landfills, apiaries, cabins, and other high-value properties. Fences, however, may be relatively expensive. Consider the extent, duration, and cost of damage. Many fence designs have been used with varying degrees of success. Electric chargers increase the effectiveness of fences.
One person can easily and quickly install an electric polytape fence (Figure 6). It is economical and dependable for low to moderate pressure from bears. The fence consists of 4 strands of electric polytape that are attached to posts with insulators.
Materials that are required to make an electric polytape fence include:
- 200-yard roll of polytape,
- 12, 4-foot fence rods (5/16-inch diameter),
- 48 insulators or clips,
- 4 gate handles,
- 12-volt fence charger,
- 12-volt deep cycle battery, and
To install the fence, drive four corner posts one foot into the ground, and attach a guy wire. Clip vegetation in a 15-inch-wide strip under the fence and apply an herbicide (use pesticides carefully near bees). Attach insulators on the inside of corner posts and stretch the polytape from the four posts at intervals of 6, 16, 26, and 36 inches aboveground. Hand-tighten the polytape and join the ends with square knots. Drive the remaining posts into the ground at 12-foot intervals, attach insulators on the outside of the line posts, and insert polytape.
A welded-wire, permanent fence (Figure 7) is durable and expensive, and used where there is high pressure from bears. Two people can install it in about 8 hours. The fence consists of heavy, 5-foot woven-wire, supported by wooden posts, and ringed by two additional electrified wires.
Materials required to construct a woven-wire permanent fence include:
- 50-yard roll of 5-foot-high, woven-wire with 6-inch mesh,
- 150-yard roll of high-tensile (14-gauge) smooth wire,
- 24, 8-foot treated wooden posts,
- 40 insulators (screw-in types),
- 2-pound box of 1½-inch fence staples,
- 6 gate handles,
- 12-volt fence charger,
- 12-volt deep cycle battery, and
To install the fence, set posts 6 to 12 feet apart in 2-foot-deep holes. Align the four corner posts at 5o angles from the vertical. Brace the corner and gate posts from the inside with H-braces or posts set at 45oangles. Clear the vegetation in a 15-inch-wide strip under the fence and apply herbicide. Place one length of welded wire vertically into position and staple the end to a corner post. Pull the entire length of wire taut with a vehicle and staple the welded wire to the line posts. Continue until all sides, except the gate opening, are fenced. Fasten 2 strands of high-tensile wire to insulators positioned 5 inches away from the welded wire, at intervals of 6 and 56 inches above ground level.
For a 12-foot gate opening, attach 3 strands of high-tensile wire to insulators on the gateposts. Space the wires at 6, 36, and 56 inches above the ground. Connect them to the two strands that were previously strung around the fence; these will be connected to the positive terminal of the fence charger. Attach 3 more wires to gatepost insulators 20, 48, and 64 inches above the level of the ground; these will be connected together and to the ground rod. Fit insulated gate handles to the free ends of all 6 gate wires.
To energize electric fences, use a 110-volt outlet, or 12-volt deep cell (marine) battery connected to a high-output fence charger. Place the charger and battery in a case to protect them against weather and theft. Drive a ground rod 5 to 7 feet into the ground, preferably into moist soil. In dry soil, multiple ground rods may be needed. Connect the ground terminal of the charger to the ground rod with a wire and ground clamp. Connect the positive fence terminal to the fence with a short piece of fence wire. Use connectors to ensure good contact.
Electric fences must deliver an effective shock to repel bears. Lure bears into licking or sniffing the wire and getting shocked by attaching attractants (peanut butter on strips of aluminum foil) to the fence. Increase grounding, especially in dry, sandy soil, by laying grounded chicken wire around the outside perimeter of the fence.
Check the voltage of the fence each week: it should carry at least 3,000 volts. To protect against voltage loss, keep the battery and charger dry and their connections free of corrosion. Make certain all connections are secure and check for faulty insulators that might cause arcing between the wire and post. Each month, check the tension of the fence and refresh attractants. Always recharge batteries during the day so that the fence is energized at night.
Habituated bears that are conditioned to food can be very dangerous. Do not use any frightening method that would threaten a bear and elicit an attack. If a frightening technique does not cause the bear to flee in a few seconds, stop and try a different method, provided you are in a safe location.
Black bears can be frightened for short periods from an area such as a building or livestock corral by use of night-lights, strobe lights, loud music, pyrotechnics, exploder canons, scarecrows, and trained guard dogs. Change the position of frightening devices frequently. Individual bears usually become habituated to them, at which point frightening devices are ineffective, and human safety becomes a concern.
Aversive conditioning requires unpleasant experiences to encourage bears to stop nuisance behaviors such as visiting landfills or getting close to urban areas. Hazing is most successful when used on bears older than one year, but before they become conditioned to food provided by humans. Tactics include chasing accompanied by yelling, throwing rocks, cracker shells, pepper spray, 12-gauge plastic slugs, gel-filled paint balls, bean bags, or 38-mm rubber bullets. Aim for the large muscle mass in the hind quarters of the bear. Avoid the neck and front shoulders to minimize the risk of damaging an eye. Safety training for firearms is recommended. Karellian bear dogs have been used effectively to haze habituated bears out of urban areas and livestock facilities.
Capsaicin spray has been tested and used effectively on black bears in close quarters and threatening encounters. The range for most products is less than 30 feet, so capsaicin is only effective in close encounters. Do not spray capsaicin on objects or in areas in an attempt to repel bears, as the spray actually may attract them. When using capsaicin spray, make sure that you are upwind of the target so that you do not suffer from the effects.
No toxicants are registered for the control of black bears.
As last resort, shooting is effective for dealing with a black bear that poses an immediate threat to safety. Permits are required in most states to shoot bears. To increase the probability of removing the individual causing the problems, shooting should be done at the site where damage has occurred. Shooting is best left to a professional or law enforcement.
Several traps are available for capturing bears. Due to the legal and technical issues involved with bear trapping, it is necessary to consult with your state wildlife agency. The culvert or barrel trap (Figure 8) is an effective trap for professional use. After capture, the bear can be immobilized, released at another site, or euthanized.
Relocation of black bears is not recommended unless the situation involves a rescue.
Any capture and translocation of bears is usually conducted by a state or federal wildlife agency. This is time consuming and expensive, and is used as a last resort for problem bears, prior to lethal removal.
Translocation of bears has a mixed record of success. Bears that have been trapped and are to be released should be transported at least 50 miles from the site, preferably across a substantial geographic barrier, such as a large river or mountain range, and released in a remote area with suitable wooded habitat. Some bears have returned from as far as 120 miles from the release site. A bear that causes problems should be released only once. If it causes subsequent problems, it should be euthanized.
Translocation often is combined with aversive conditioning. Bears transported in culvert traps can be shot with rubber buckshot or gel-scram paintballs when released.
If necessary, bears should be euthanized by shooting or chemical induction.
Black bear, NWCO, wildlife control, wildlife damage management