A Northern Pacific Rattlesnake (Crotalus oreganus oreganus) is curled up on the leaves.

Pierre Martineau writes:
"This is likely a Northern Pacific Rattlesnake (Crotalus oreganus oreganus), pretty much the only rattlesnake species we are likely to see in the Bay Area. It used to be considered a subspecies of the Prairie Rattlesnake (Crotalus viridis oreganus).


David Paul Bernstein adds:
"Those are beautiful pictures! I agree with everything Pierre said pretty much. The Northern Pacific Rattlesnake is the only show in town. In fact, you have to go fairly far south before you find anything else (Mojave, Sidewinder, Southern Pacific). It's fairly young and looks to have a VERY fresh skin on.

"I can't swear that the Northern Pacific was never considered a subspecies of the Prarie Rattlesnake (C. Virilis Oreganus) but my impression was that both the Prarie and the Northern Pacific we're considered subspecies of the rather all encompassing Western Rattlesnake (C. Virilis). Check out Stebbins Map 189 for the old nomenclature and range maps. The rattlesnakes have been so rearranged and divided into new species that most people just say the hell with it, I think."