Larry from Riverton writes:  My niece Judy sent me this, wow be careful out there in the hills this spring. Yesterday the family went out in the hills east of Riverton. We were rock hunting and picnicking and enjoying a spring day. Patrick, our son in law  yelled out saying, "come look at this big den of snakes". We all tip-toed in that direction for a look. Here is what we saw.

                    
Mike in Lander got these photos from a friend.  He had no other info....anyone?