Description Crotalus

the rattle of western diamondback rattlesnake (notice black , white coloring on lower right)

the rattle consists of series of loosely interlocking hollow shells, each of @ 1 point scale covering tip of tail. in other snakes, tail tip, or terminal spine, cone-shaped, hardly thicker rest of skin, , shed along @ each successive molt. in case, however, end-scale, or button , thicker , shaped bulb, 1 or 2 annular constrictions prevent falling off. before each molt, new button have developed inside last 1 , before skin shed, tip of new button shrinks, thereby loosening shell of previous one. process continues succession of molts produces appendage consisting of number of interlocking segments make audible noise when vibrated. since younger specimens may shed 3 or 4 times in year, every time adding new segment rattle, number of segments bears no relation age of snake. in theory, rattle become long indeed, in practice, older segments tend wear out , fall off. how happens depends on snake s environment, end segments tend break off after rattle becomes 6 or 7 segments long; uncommon find specimens many dozen segments. in captive specimens, however, many 29 segments have been found.