A little bit later on, I got a glimpse of a Twin-spotted as it disappeared into the rocks, but of course no photo. Then I heard a voice, and saw someone calling to me. I met the fellow, who turned out to be Dave Prival of the University of Tucson. Dave is one of the few scientists in the world studying Crotalus pricei. Not surprisingly, he happened to have a recently captured specimen, which he kindly allowed me to photograph. This one was a yearling, about 10 inches long.