An increasing number of backcountry hikers carry pepper spray as a possible deterrent against aggressive bears. This aerosol red pepper derivative affects an animal's upper respiratory system and mucous membranes, triggering temporary incapacitating discomfort. Throughout North America, pepper spray has apparently repelled aggressive or attacking bears. However, there are accounts where pepper spray has not worked as well as expected.
Many factors influence the effectiveness of pepper spray.
Spray distance, wind, wet or rainy weather, extremes of heat or cold, and product shelf life all may affect its usefulness. The decision to carry pepper spray as a bear deterrent comes down to a personal choice. If you decide to carry spray, it is your responsibility to use it wisely and only in situations where aggressive bear behavior justifies its use. Check with your local authorities. You can purchase pepper spray from most sporting goods stores in Montana, Wyoming, and Idaho.