The rattle is the distinctive feature of many venomous snakes. In adults the rattle is made up of loosely attached horny segments that strike against one another to produce a buzzing sound when the tail is vibrated rapidly. In the very young snakes, the rattle is more like a "button". It is a myth that you can tell the age of a rattlesnake by the number of segments in its rattle. A new segment is added each time the skin is shed; the segments become increasingly larger until the snake reaches adult size. Two to four new segments are added to the rattle each year. The rattles can break off if damaged.
Snake rattles have been used by Native Americans for decorations and for ceremonial or festive purposes.