Touch the rattlesnake's rattle

Touch the rattlesnake's rattle—not the rattle of a snake you encounter on your hiking trail, but the enlarged model shown here as it is displayed in the Arizona-Sonora Desert Museum. The cross-section clearly demonstrates the segments of the rattle. Rattlesnakes add a new segment every time they shed their skin. As a panel next to the model explains, the rattle [of a real rattlesnake] is hollow, dry and feels something like heavy parchment. It is made of keratin, a fibrous protein that, in other animals, makes feathers, hair, horns, and nails. Segments loosely interlock; when vibrated their clashing creates the sound. The vibration increases with air temperature. At any temperature, you should be alarmed if you hear the rattling from somewhere next to your trail.