Otospermophilus beecheyi (Richardson, 1829), the California ground squirrel (formerly, Beechey ground squirrel), is dorsally brown with silver spotting. This facultatively social and ecologically flexible species occurs at a range of elevations, has a wide dietary niche, and is common in California grasslands and oak woodlands. Although listed as “Least Concern,” it has a tenuous relationship with humans. It contributes to crop and infrastructure damage and is associated with the spread of zoonoses, including plague. Nonetheless, it is an important prey species for mammalian, reptilian, and avian predators and an ecosystem engineer that constructs burrows that benefit commensals. Ongoing study of its behavioral ecology continues to advance our understanding of mammalian antipredator behavior, disease transmission, behavioral plasticity, and social evolution.