And somebody mentioned that rattlers will only strike at something warm - also not true. They're pit vipers that use their heat sensors to track prey (pretty useful since they mosty hunt at night) but for self-defense purposes they'll strike at movement. On more than one occassion I've seen rattlers strike at the object I was using to relocate them. 
thank you for sharing your experience.
i always like to find the science behind the issues.
i actually found that we're both on the right track.  a scientific study - blindfolded snakes ? ! - is found   
here.  seems their vision and heat and smell sense contribute to their dietary intake.