Lampropeltis getula californiae
You never know quite when you'll run into a king snake, but chances are it will be spring or early summer, and it will quietly continue on its own way if you approach it. They are relatively common in faculty housing, and along the campus trail, usually just basking, but can sometimes be seen constricting and eating other snakes or lizards, or even a gopher--much to the gratitude of gardeners everywhere.
The coloration and pattern can vary somewhat on this snake, but chances are if you see this striking bands of dark and light, it's a California king snake.
Photo Credit: Amanda Sparkman