During July and August, near ear-splitting calls of cicadas fill the air during the day only to be replaced by the incessant buzzing of katydids at night. People in the south call cicadas “July flies,” with the accent on the “u” of July. Male July flies and katydids call to attract mates, and they all call at once in their frenzy to attract females carrying the most eggs. A few snakes are also “buzzers.” Rattlesnakes “buzz” for a very different reason, and they are more likely to rattle when it is hot, simply because their body temperatures are high and thus they are very active.
Rattlesnakes rattle when they are disturbed, and the loud sound has several defensive functions. One of course is simply a warning—“stay away because I am dangerous.” This function is similar to bright coloration of poison frogs and some mushrooms, warning of impending danger. From the perspective of the snake, if it wards off a potential attack, then it has saved the snake some energy defending itself. The sound also directs the attention of a potential predator away from the vulnerable parts of the snake (head and body) so that if an attack does ensue, the snake may be partly down a hole or under a rock by the time a predator figures out that the sound-producing end is the tail. The rattle is composed of overlapping rings of dead skin. Each time a rattlesnake sheds its skin, it adds a rattle. Rattles sometimes break off, so a large snake might have a short rattle. Some wives’ tales (perhaps more correctly, old drunk husband’s tales!) are that rattlesnakes get a new rattle each year and that rattlesnakes have to rattle before striking. Neither is true.
Science often goes through wives’-tale stages as well. Rattlesnake rattles were first believed to attract cicadas, which they supposedly ate. However, they don’t eat cicadas, so that was false. They were thought to attract mates, but snakes do not have ears, and we don’t hear choruses of male rattlesnakes during the breeding season, so that too was proven false. The nice thing about scientific theories, no matter how ridiculous they may seem, is that once proven false, they are usually discarded. Many non-scientific myths are not only passed on from generation to generation, they are usually embellished with time, often to the point that people believe them no matter how ridiculous they might be.
So, if you should have the fortune of hearing a rattlesnake while out hiking around, first move away, keeping in mind that the snake is letting you know that you are too close. Once you are a safe distance, see if you can locate the snake and add it to your life list of interesting sightings.