Bear Mortality

Bears are not just an interesting animal: because they rely on healthy forests to survive, they are also an excellent indicator of forest health. Aside from the success or failure of forest forage crops (the foods bears eat, such as berries and nuts), other factors that may influence bear mortality include bear population size, new development of human homes and cities, and timing of when bears wake-up from hibernation.

In the Forest Health Index, bear mortality refers to the number of bears found dead from January through August, the season during which bears cannot legally be hunted. These deaths may be caused by natural events, roadkill, bears put down by federal or state officials, bears killed by landowners, or unknown causes.

What We're Seeing

Extraordinarily high: Bear mortality was extremely over the past five years. Few or no other periods with such high bear mortality exist on record for this region. The high mortality could result from either unusually large bear populations for the area or very poor conditions for bear survival, including failed food supplies of acorns and berries, increasing conflicts with growing human populations, or natural disasters such as drought or wildfire.

What We're Monitoring

Since 1981, bear mortality has increased, although the number of deaths varies from year to year. Bear mortality represents other forest conditions, like the abundance of acorns and berries, but it also represents an important risk to human safety. As Colorado’s human population, city development, and recreational activities continue to grow, people who live and play in Colorado may increasingly need to make choices to prevent humans and bears from interacting in ways that may be dangerous to both.

Future Outlook

Climate models show temperatures continuing to rise in Colorado in the coming years. For bears, warmer days at the end of fall or start of spring might mean a shorter time spent in hibernation—with the potential outcome being that bears are awake and hungry for longer periods of time. Yearly fluctuations in precipitation can also impact berry and acorn production, leading to changes in how far bears travel to find food. Meanwhile, growing human populations at the edges of natural areas has the potential to increasingly bring bears and people into conflict. There are many things individuals can do to help prevent bear mortality. Keeping garbage cans inside or using bear-proof containers, avoiding leaving snacks in cars with open windows, and maintaining a safe distance from bears and other wildlife can help reduce dangerous encounters and prevent bears having to be either relocated or put down.