Colorado is home to the American Black Bear, with an estimated population of 17,000 to 20,000 animals. The state has not had a population of grizzly bears since 1979, meaning nearly all bear encounters involve the black bear species. As human populations expand into bear territory and development increases, the number of human-bear conflicts has risen significantly. Understanding bear behavior and safety measures is relevant for both residents and visitors.
Documented Bear Attacks in Colorado
The number of bear attacks resulting in human injury or fatality in Colorado remains extremely low compared to the thousands of bear sightings and conflicts reported annually. Colorado Parks and Wildlife (CPW) receives thousands of reports of bear activity each year, but the vast majority do not involve physical contact with people. For example, CPW received over 5,000 reports of sightings and conflicts, with over half involving bears accessing trash.
Fatal attacks are rare, with only four documented fatalities caused by wild bears in Colorado since 1971. The most recent fatal attack occurred in 2021. Non-fatal attacks and injuries occur, but they represent a small fraction of total human-bear conflicts recorded. These incidents often involve minor injuries resulting from surprising a bear at close range or a bear defending a food source.
Understanding the Causes of Bear Encounters
Bear encounters that lead to injury fall into two categories: defensive reactions and incidents involving food-conditioned bears. The majority of physical confrontations are defensive, occurring when a bear feels threatened and acts to neutralize the perceived danger. This often happens when a person inadvertently surprises a bear at close range, such as rounding a corner on a trail or approaching a sow with her cubs.
Defensive behavior also occurs if a person gets too close to a natural food source the bear is guarding, such as an animal carcass. The bear’s primary goal is to make the threat leave, which can involve bluff charges, jaw-popping, or huffing sounds before physical contact. However, the most prevalent cause of human-bear conflict is a bear seeking easily accessible human food sources, not a defensive reaction.
Bears have a strong drive to consume calories, especially during late summer and fall as they prepare for hibernation. When bears repeatedly find unsecured items like trash, bird seed, or pet food, they lose their natural wariness and become “food-conditioned.” These habituated bears cause many conflicts, including property damage and entering dwellings, which can escalate into dangerous situations.
Safety Guidelines for Living and Recreating in Bear Country
Minimizing the availability of human attractants is the most effective way to reduce bear conflicts around homes. Residents should secure all garbage in a bear-resistant container or store it in a garage or shed until collection morning. Other attractants, such as bird feeders, pet food, and barbecue grills, must be removed or cleaned thoroughly between April and November when bears are most active. Picking up fallen fruit also removes a food reward that can draw bears into residential areas.
When recreating outdoors, hikers and campers should make noise by talking or calling out to alert bears to their presence, which helps prevent accidental surprise encounters. It is helpful to hike in groups and keep dogs leashed at all times, as off-leash dogs can provoke a bear and lead it back to their owner. Campers must store all food, toiletries, and scented items away from tents in bear-resistant canisters or hung from a tree at least 100 yards from the sleeping area.
If a bear is sighted at a distance, the safest action is to quietly leave the area without drawing attention. If a bear approaches, people should stand their ground, wave their arms to appear larger, and speak firmly to haze the animal away. Running away should be avoided, as this can trigger a chase response. If a bear continues to approach within forty feet, bear spray should be deployed, aiming slightly downward at the bear’s face. In the rare event of a physical attack by a black bear, fighting back aggressively is the recommended response.