Ixodes pacificus, or the Western black-legged tick, is a small arachnid prevalent in the western United States, especially in forested and brushy areas. Known for its role as a vector of Lyme disease, it displays a distinctive dark brown body with a black scutum. This species primarily feeds on mammals, birds, and reptiles, playing a crucial role in the transmission of tick-borne diseases.

Ixodes pacificus, commonly known as the Western black-legged tick, is native to the western coastal regions of North America. It is primarily found along the Pacific coast of the United States, including states like California, Oregon, and Washington. The tick's range also extends into parts of British Columbia in Canada.

Ixodes pacificus typically inhabits areas with a temperate climate. Its preferred environments are moist woodland, grassland, and shrubland areas. The tick thrives in regions with dense vegetation and leaf litter, which provide the humidity and shelter necessary for its survival.

The Western black-legged tick is primarily a vector for pathogens such as Borrelia burgdorferi, the causative agent of Lyme disease. It plays a crucial role in the ecosystem by acting as a parasite on various mammals, birds, and reptiles, facilitating the transfer of pathogens between these hosts. The tick's lifecycle involves multiple hosts, including small mammals like rodents and larger mammals such as deer, which are essential for its development and reproduction.