<P> According to Rubio, "The most widely accepted hypothesis for the evolution of the rattle is that the rattle is a warning device for predatory animals that might be a threat to the rattlesnake . It produces a signal to drive them away ." </P> <P> 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, making the rattling noise (which is amplified because the segments are hollow) in a behavior known as tail vibration . The muscles that cause the rattle to shake are some of the fastest known, firing 50 times per second on average, sustained for up to three hours . </P> <P> At birth, a "prebutton" is present at the tip of the snake's tail; it is replaced by the "button" several days later when the first skin is shed . However, no sound can be made by the rattle until a second segment is added when the skin is shed again . A new rattle segment is added each time the snake sheds its skin, and the snake may shed its skin several times a year, depending on food supply and growth rate . </P> <P> Rattlesnakes travel with their rattles held up to protect them from damage, but in spite of this precaution, their day - to - day activities in the wild still cause them to regularly break off end segments . Because of this, the age of a rattlesnake is not related to the number of rattles on its tail . </P>

When does a rattle snake get its rattle
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