This is an amalgamation of observations made from the 2012 season: The behavior seen in this video is representative of 90% of my experience approaching timber rattlesnakes in the field for observation; they will either slowly uncoil and slink away quietly beneath a favored shelter stone, or they slither to safety while rattling at the same time. However, rattling is an inherently risky behavior; it is a dinner bell to some while serving to incite aggression from others. Rattling is beneficial for a rattlesnake when dealing with a potential or immanent trampling threat, it is largely accepted that the rattle evolved during the Pleistocene when plentiful megafauna posed a crushing threat to a camouflaged (basking or ambush ready) rattlesnake. The rattle is an imposing sound and suffices to warn other animals of the snake’s whereabouts when the threat of retaliation is little to none.
Biting a non-food item is possibly the most expensive of potential outcomes for the snake. Venom takes time and metabolism to recover after spending it on a defensive reaction that could have been avoided if the snake was silent. This is likely the reason why some snakebites result in no venom being delivered in what is known as a dry bite. The metabolism involved in recouping wasted venom would be much better served developing embryos in a vitellogenic female, recovering from a wound, growth and ecdysis, osmoregulation, respiring, or securing a meal. It is because of the two aforementioned consequences that a rattlesnake prefers to rely on camouflage or a stealthy escape instead of bringing unnecessary and potentially costly attention to itself. I can literally count on one hand the amount of times a timber rattlesnake I was simply observing has attempted to bite me, and that is a generous estimate.
This video illustrates the behavior assumed by timber rattlesnakes when approached. None of these snakes were touched, moved, or otherwise messed with in any way. What is seen in this video is a mix between silent escape, flight while simultaneously rattling, and in once instance when a snake was fully exposed, there is a sort of hybridization between defensive and offensive readiness as the snake quickly escapes backwards into a nearby shelter. Also, in the previous video, I showed baby timber rattlesnakes emerging, basking, and adjusting themselves. The last clip of this video is the end of that scene, which shows the coiled neonate literally jump down into its shelter as I approached to retrieve my camcorder. This video clearly illustrates that if there is a way to avoid a threat, then the snake will favor escape above standing its ground.
Penn Plax REPSH2 Large Classic Glass Snake Cage