Source: https://www.flickr.com/photos/shelly2dogs/7740446748/

Western black-headed snake (Tantilla planiceps), also known as the California black-headed snake, is a snake species endemic to the Californias (the U.S. State of California and the Baja California Peninsula in Mexico), as north as the San Francisco Bay and as far east as western Utah. The western black-headed Snake is a member of a larger natural group of small New World terrestrial colubrids, where some of the related species include sand snake (Chilomeniscus), shovel-nosed snake (Chionactis), and the ground snake (Sonora). The western black-headed snake is the sister species of Tantilla yaquia of southern Arizona. They are also related to Tantilla gracilis, Tantilla atriceps, Tantilla hobartsmithi and Tantilla nigriceps, all species endemic to the southwestern United States. It is visually similar to the Southwestern Black-headed Snake (T. hobartsmithi). Order: Squamata, Suborder: Serpentes, Family: Colubridae, Genus: Tantilla, Species: Tantilla planiceps (Blainville, 1835).