Black Bears and Grizzly Bears
Black and grizzly bears prey on livestock. Black bears usually kill by biting the neck or by slapping the victim. Torn, mauled, and mutilated carcasses are characteristic of bear attacks. Often, the bear will eat the udders of female prey, possibly to obtain milk. The victim usually is opened ventrally and the heart and liver are consumed (Bowns and Wade 1980). The intestines are often spread out around the kill site, and the animal may be partially skinned while the carcass is fed upon. Smaller livestock such as sheep and goats may be consumed almost entirely, and only the rumen, skin, and large bones left. Feces are generally found within the kill area, and a bedding site is often found nearby. Bears use their feet while feeding so they do not slide the prey around as do coyotes. If the kill is made in the open, it may be moved to a more secluded spot.
The grizzly has a feeding and killing pattern similar to that of the black bear. Murie (1948) found that most cattle are killed by a bite through the back of the neck. Large prey often have claw marks on the flanks or hams. The prey’s back is sometimes broken in front of the hips where the bear simply crushed it down. Young calves are occasionally bitten through the forehead. The presence of bears has stampeded range sheep, resulting in death from suffocation or from falls over cliffs. A marauding bear searching for food may also play havoc with garbage cans, cabins, camp sites, and apiaries (Maehr 1983).
Black bear damage to trees can be recognized by the large vertical incisor and claw marks on the sapwood and ragged strips of hanging bark. Pole-size trees to small saw timber are preferred. Most bark damage occurs during May, June, and July (Packham 1970). After the bark is pulled away, bears will scrape off the cambium layer of the tree with their incisor teeth, leaving vertical tooth marks (Murie 1954).
The bear track resembles that of a human, but has distinctive claw marks. The little inside toes often leave no marks in dust or shallow mud so the print appears to be four-toed (Murie 1954).
Summary of Damage Prevention and Control Methods
Exclusion
Use heavy, chain-link or woven-wire fencing topped with barbed wire and buried at the bottom. Add outriggers and electrified wires to the outside perimeter. Metal (bar) cages and metal buildings will protect workers, food, and other attractants.
Cultural Methods
Keep threatened areas free of all attractants. Establish campsites, bee yards, and livestock bedding areas away from vegetation or other cover. Use proper solid waste management procedures. Prevent any rewards to bears, and immediately discourage all approaches by bears.
Frightening Devices
Boat horns, cracker shells, rifle shots, helicopter chases, yard lights, strobe lights.
Repellents and Deterrents
Capsaicin spray. Install “early warning” or detection systems around field stations or campsites. Use trained dogs to detect or deter bears. Use plastic slugs to deter bears.
Toxicants
None are registered.
Fumigants
None are registered.
Trapping
Use culvert traps or foot snares; for bait use only wild animal road kills and scents.
Immobilizing and Handling
Drugs used on bears are strictly controlled, require licensing, and are potentially dangerous to the animal, the drugging team, and unauthorized users. Post-immobilization care is very important.
Shooting
Weapons that offer the best protection are high-powered rifles of .350 caliber or larger, and 12-gauge pump shotguns with rifled slugs. Handguns (.44 magnum) should be carried only for quick defense.
Other Methods
Aversive Conditioning. Captured and confined bears can be trained to fear and avoid humans through repeated confrontations and the use of repellents. Properly trained personnel and holding facilities designed for aversive conditioning are required.
Public Education
Implement programs to promote the prevention of bear problems.
Avoiding Human-Bear Conflicts
Avoid bear encounters by staying alert. Never approach bear cubs. Avoid high bear-use areas. Eliminate bear attractants.
