rattle snakes not rattling

It's not so much adaption as it Evolution.. It's simple Darwinism "Survival of the fittest!"

As more and more hogs populate the state they begin having effects on Herpetofauna(amphibians and snakes) I recently wrote an abstract for school on a research paper , "depradation of Herpetofauna do to Feral Hogs".. They stated in that study that in the 65 hogs analyzed; they were able to calculate they had an overall of 254 hours grazing time and in that time 150 different Herpetofauna were consumed, consisting of 5 separate species.. 3 frogs and 2 snakes!

That being said as more hogs eat/kill the rattlesnakes that do rattle and announce their presence they are selectively choosing them and allowing the snakes that don't give the "rattle warning" to live. These " quiet" rattlesnakes then pass on their genes leading to more non-rattling snakes and so on...