Was a rattlesnake (as confirmed by rangers. Also could see the rattle). Very calm snake. According to rangers, it's a subspecies of rattlesnake that is native only to the Grand Canyon(Crotalus oreganus abyssus). This has been changed and the subspecies is included as part of the Great Basin Rattlesnake (as per comments) This one was likely young; rattle was small as was the snake
C. eriophylla