Identifying Grizzly Bear Sign and Damage


Brown (grizzly) bears have many unique behaviors that subject them to situations in which they are perceived as a threat to humans or personal property. They are opportunistic feeders that may switch to scavenging human-produced food and garbage if made available, becoming a problem around parks, camp grounds, cottages, suburban areas, and garbage dumps. Bears that are conditioned to human foods become used to the presence of humans and are therefore the most dangerous.

 Bear activity is intensely oriented to the summer months when people are also most active in the mountains and forests. Brown bear attacks have resulted in injuries ranging from superficial to debilitating, disfiguring, and fatal. Dr. Stephen Herrero documented 165 injuries to humans resulting from encounters with brown bears in North America from 1900 to 1980. Fifty percent of the injuries were classified as major, requiring hospitalization for more than 24 hours or resulting in death. In addition to the 19 grizzly bear-inflicted deaths that Herrero reported, two Department of Public Safety employees reported 22 deaths in Alaska.

Brown bears also occasionally cause problems around orchards, bee yards, growing crops, and livestock. Some bears occasionally kill cattle, sheep, pigs, horses, goats, and poultry, but most do not prey on livestock. Bears kill livestock by pursuing them at high speed, slashing from the rear and pulling the prey down. They hold the prey with their own weight while biting the head or neck area and delivering blows. The ventral area is then ripped open, and the hide sometimes skinned, sometimes devoured along with subcutaneous and visceral fat. Bears eat large volumes of flesh and body parts, leaving many large scats. Adult brown bear scats are 2 inches  or more in diameter. The bear will often cover the remains with all types of nearby debris—vegetation, leaves, sticks, and soil, and then bed nearby. The investigator should look carefully for (and record) all wounds, tracks, hairs, and any other sign that would prove bear predation. It is important to document accurately the cause of death, the manner of killing, and all signs in the area that would indicate predation by bears. The lack of any such evidence should preclude brown bear control.

Sheep predation may be more subtle to document since, when frightened, sheep readily stampede and injure or kill themselves on felled timber or cliffs. In such a case, examiners should look carefully for neck and head bites, or smashed skulls, as well as tracks, bear hair, bear droppings, and other sign. Survey the overall scene—the flight path of the sheep, the place of cover and possible attack relative to the flight route, the amount consumed, and the freshness of any flesh or tissues in the bear droppings.

Grizzly bear attacks are often easily identified by tracks alone. The foot prints are very large, with claw marks on the front foot extending up to 4 inches in front of the toe marks. The toes of a grizzly are in a much straighter line than those of a black bear, and the grizzly paw includes greater “webbing” between the toes, which may show up in a mud print. Grizzly hair found in the area is another positive identifying characteristic. Look carefully on the ends of broken sticks, in rough areas on logs, under high logs, in the bark of trees, or in any pitch patches on conifers where a bear may have rubbed. Also check the barbs of any wire fencing nearby. All hair should be collected carefully in small envelopes and sent to a wildlife agency or university lab for identification.

Most bear depredations are easily identified, especially if there is wet or soft ground in the area. Bears are not sneaky—they march right in and take what they consider is theirs.

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