Why does a Rattlesnake's Tail make noise?

 Generally, the snakes we see are elusive and do not make many sounds, but the rattlesnake is special. It is a kind of poisonous snake, and its tail makes noise. Do you know why?

As the name suggests, the rattlesnake makes a sound from its tail, and its tail is also called a rattle. 

The rattle serves as a warning for predators of the rattlesnake.  The rattle is composed of a series of hollow, interlocked segments made of keratin, which are created by modifying the scales that cover the tip of the tail. The contraction of special "shaker" muscles in the tail causes these segments to vibrate against one another, thus making the rattling noise (which is amplified because the segments are hollow) in a behavior known as tail vibration. The muscles which cause rattling are some of the fastest known, firing 50 times per second on average, sustainable for a duration up to three hours. 

But in more heavily populated and trafficked areas, reports have been increasing of rattlesnakes that do not rattle. This phenomenon is commonly attributed to selective pressure by humans, who often kill the snakes when they are discovered. Nonrattling snakes are more likely to go unnoticed, so survive to reproduce offspring that, like themselves, are less likely to rattle.

So we call on everyone to protect nature and let our animals maintain their original characteristics, so that we can live in harmony for a long time. 

coppertist.wu made a metal pendant according to the model of the rattlesnake rattle, calling on everyone to protect our nature at all times, let them survive forever, and don't let our descendants only find them in books.