Worldwide, few snakes are as readily recognizable or as well-known as the rattlesnake.
There are thirty recognized species and subspecies in the U. S. varying in size from the diminutive Desert Massasauga Rattlesnake (Sistrurus catenatus edwardsii) with adults less than 22 inches long, to the always impressive Eastern Diamond-backed Rattlesnake (Crotalus adamanteus) with adults often more than five feet long.
Regardless of size, and contrary to folk belief and Hollywood portrayal, rattlesnakes are rarely aggressive in the human behavioral sense of the word. In most rattlesnake-human encounters, the rattlesnake is more often passive or, at most, defensive. Many lie quietly motionless, as behavioral evolution has dictated, in order to allow their cryptic color and pattern to render them difficult to see. Others try to crawl away to safety. Virtually all, however, will defend themselves when the need arises. It’s important to remember that the need for self defense is as the snake sees it, not as we see it.
As a rattlesnake defends itself, it may rattle, attempt to intimidate through posturing, or, if the intruder persists, bite. Relying on its camouflage to remain undetected, crawling away to safety, trying to intimidate, or delivering a bite are the only self-defense options available to a rattlesnake approached by a potential predator such as one of us.
Can you depend on a rattlesnake to always rattle as you approach it?No.
Will a rattlesnake always bite a person who has approached too closely?No.
Will a rattlesnake actually advance toward a person with the intent to bite?Most often, no.
On occasion, an individual rattlesnake does react in this way. This seems most common with rattlesnakes being continually harassed as they try to escape. Others in this circumstance become so intimidated that they coil with both their head and tail concealed from view.
Rattlesnake temperament varies across a scale from relatively laid-back to excitable. The words “always” and “never” are not reliable in describing their behavior. Those who say that a rattlesnake, or that an individual of a given species, will always or never adopt a given behavior have not yet encountered enough rattlesnakes, or enough individuals of the species concerned.
Even with the range of temperament and behavior that is possible, it seems safe to say that most rattlesnakes will be found to most often reside somewhere toward the more passive end of the scale. It was recognition of this phenomenon, along with the deadly result that could come from a rattlesnake defending itself, that caused the American colonial rebels to adopt the Timber Rattlesnake (Crotalus horridus) as a symbol. The “Don’t Tread On Me” flag, widely used during the American Revolution and well known today, recognized the fact that the snake was not itself aggressive and wished only to be left to its own devices, yet was capable of a deadly response to aggression when the need arose.
In spite of this early recognition, folklore persists to this day of the aggressive, ever-ready-to-attack rattlesnake. This seems especially true in areas where a notorious local species is often given this role. For example, in much of the southwestern U.S., the Mojave Rattlesnake (Crotalus scutulatus) is often said to unfailingly “chase you.”
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