The Rocky Mountain wood tick, also known as Dermacentor andersoni, is a common tick found in the western United States and parts of Canada. These ticks thrive in grassy and wooded areas, especially in mountainous regions. They are known for their distinctive brown color and can grow up to 1/4 inch in size when fully engorged with blood. Rocky Mountain wood ticks are most active during the spring and early summer months. They are known carriers of several diseases, including Rocky Mountain spotted fever and tick-borne encephalitis. It is important to take precautions when spending time outdoors in areas where these ticks are prevalent, such as wearing protective clothing and using insect repellent.