The western gray squirrel is a tree squirrel found along the western coast of the United States and Mexico. In some places, this species has also been known as the silver-gray squirrel, the California gray squirrel, the Oregon gray squirrel, the Columbian gray squirrel and the banner-tail. There are three geographical subspecies: S. g. griseus ; S. g. nigripes ; and S. g. anthonyi.