I’m afraid I have no more information, and I’m not as familiar with this species as you obviously are! The photo is on the Yellowstone web site. The location of the photo shoot is not provided. Why would the Yellowstone site feature animals from other locations? No idea.
Is that photo taken in Yosemite or Yellowstone? On the page it says Yosemite National Park’s website!
Prairie Rattlesnakes (Crotalus viridus viridus) live in Yellowstone
Northern Pacific Rattlesnakes (Crotalus viridus oreganis) live in Yosemite
http://mowryjournal.com/2014/06/04/the-animals-of-yellowstone/prairie-rattlesnakeroy-wood1990/#respond
I’m afraid I have no more information, and I’m not as familiar with this species as you obviously are! The photo is on the Yellowstone web site. The location of the photo shoot is not provided. Why would the Yellowstone site feature animals from other locations? No idea.