The southern Pacific rattlesnake generally grows to 30 to 44 inches in length and is highly venomous.

Like most other rattlesnakes, they are generalist feeders and occupy a wide range of habitats, except deserts/extreme arid environments. Habitats include: coastal scrub, montane forests, oak savanna, chaparral and inland valleys west of the Mojave Desert & Sierra Nevada Mountains. They also inhabit Catalina Island where they can be much darker than on the mainland.

The venom of the Southern Pacific rattlesnake varies substantially between populations likely depending on habitat. In certain areas, this subspecies of C. oreganus has developed neurotoxic venom. You can also see on the map that this rattlesnake can only be found in California and Baja California.

Southern Pacific rattlesnakes are one of the few rattlesnakes which breed in the Spring, Summer and Fall. Most others typically breed in the late Summer or early Fall, depending on species and range.