Death Valley is a prime venue for snakes. The heat and the terrain are perfect factors to make them feel very comfortable. There are many different types of snakes in Death Valley, and one of the most ideal places for this is Mesquite Sand Dunes. These dunes are near the Stovepipe Wells Village, and its a short drive from the hotel in the village. It covers a pretty big area, and a lot of people visit, so to get a nice dune with no foot prints, you have to go out pretty far. Unfortunately, walking on the dunes is pretty difficult, especially in the heat, and even more so if you're not completely in the best shape (as I am not). Given that, most people opt to go in the morning, because the sun is behind them, and makes better pictures. However, morning dawn is party time for sidewinder rattlesnakes.
I used to live in Malaysia, where they have a special 911 for snake problems. Snakes are pretty regularly found in houses and urban areas. When we lived there, we had to deal with a few of them in house. I've always had a trauma with snakes, and knowing that they could creep up on me at the Mesquite Sand Dunes did not really sit well with me. Even though many people keep saying that 'snakes are more afraid of you then you of them' - there was no way I was going to the dunes, by myself, in the morning, in the dark not being able to walk very fast in the sand. So - I convinced myself that it would be more crowded in the morning anyway, since most people would prefer the morning light and decided to go in the evening. It was hotter, but small price to pay for not encountering any of the slithering serpents.... and as you can see, the light isn't too bad at all.