Snakes aren't such opportunists like the coyote is. A coyote eats about anything at about any time it can. A coyote needs to eat often where as a snake normally only eats about 1 meal per week, depending on the size of the meal it gets. Usually, a diamondback will strike and inject poison into it's victim, only to have the bittin victim run away to die from the poison, and then the snake "tracks" its victom down and eats it, after it has already died!
I've never read anything about any snake reasoning that if it hears something in distress, it goes to it expecting an easy meal!