Yes, indeed, roadrunners regularly chow down on rattlesnakes and, no, it's not because they are immune to venom.
According to Palmspringslife.com, with rattlesnakes roadrunners are especially cagey. Jim Cornett, the curator of natural science at the Palm Springs Desert Museum, watched a sidewinder strike at a roadrunner one day and the bird caught the serpent in mid-strike, grabbed its top jaw so tightly that the snake couldn't use its fangs.
Then it whipped the snake over and over on the ground, eventually breaking the spinal column in five or six places. "They do this with everything” says Cornett. "They just try to break their prey's body, it's very effective."
Roadrunners have been observed beating rattlesnakes against the ground for up to an hour and a half. Then, they slurp those snakes down just like spaghetti. Or they take them home to the kids, and let them do the slurping. Roadrunners have potent stomach juices which break down those rattlesnakes, tarantulas and black widows. It results in quick-energy road fuel. What about the poison in the prey? According to Cornett, these poisons are actually high in protein and don't affect the roadrunners at all.
Tip! Learn how to identify Greater Roadrunner, its life history, cool facts, sounds and calls, and watch videos from Allaboutbirds.org.