Colorado’s diverse landscapes are home to a variety of wildlife, including bears. Many people wonder which bear species inhabit the state, especially given historical accounts. Understanding the types of bears present and their behaviors is important for both wildlife enthusiasts and residents sharing their environment with these animals.
Colorado’s Only Bear Species
The American black bear, Ursus americanus, is the only bear species living in Colorado. Despite their name, these bears exhibit a wide range of colors, often leading to misidentification. Grizzly bears (Ursus arctos horribilis), a subspecies of brown bear, were once present but are now considered extirpated, meaning locally extinct. The last confirmed grizzly in Colorado was killed in 1979.
Colorado’s black bear population is estimated between 17,000 and 20,000 individuals, and is considered stable or growing. Black bears inhabit nearly all forested regions, including mountainous areas, forests, and riparian zones. They are also found near human habitation as urban areas expand into their natural range.
Characteristics of Colorado Bears
Colorado’s black bears vary significantly in fur color, from black to brown, cinnamon, blonde, or honey-colored. In some areas, up to 90% are shades of brown. Adult males typically weigh around 275 pounds, while females average about 175 pounds, though weight can fluctuate from 100 to 450 pounds depending on season and food availability. On all fours, they stand about three feet high, and can reach five feet when standing on their hind legs.
Black bears are omnivores; over 90% of their natural diet consists of plants like grasses, berries, nuts, and fruits. They also consume insects and scavenged carcasses. Their exceptional sense of smell, 100 times more sensitive than a human’s, allows them to detect food from miles away. Black bears are solitary, except for females with cubs.
Most black bears in Colorado are active from mid-March through early November, hibernating in winter. They retreat to dens, called hibernacula, found in hollow logs, under tree roots, or in rock crevices. Hibernation is a period of reduced metabolic activity, where heart rate and body temperature decrease significantly. During late summer and fall, bears enter hyperphagia, intensely foraging for up to 20 hours daily to consume roughly 20,000 calories, building fat reserves for winter.
Coexisting with Bears
Living in Colorado means sharing space with black bears, so preventing human-bear conflicts is important for both people and wildlife. Conflicts often arise when bears are attracted to human food sources like garbage, pet food, and bird feeders. Securing all trash in bear-resistant containers and storing pet food indoors deters bears. Removing bird feeders during active bear seasons, typically March to November, also reduces attractants.
When hiking or camping in bear country, make noise to avoid surprising a bear. Carrying bear spray and knowing how to use it provides an extra layer of safety. If an encounter occurs:
Remain calm, stand still, and speak in a normal tone of voice.
Slowly back away while facing the bear, ensuring it has an escape route.
Never run from a bear, as this can trigger a chase response.
If a black bear attacks, fight back with anything available.
Reporting aggressive or problematic bear behavior to Colorado Parks and Wildlife aids wildlife management.