|MadSci Network: Zoology|
Sorry I took so long to answer, been swamped with my snake research. Yes, the rattle can be lost, either from a predator or whatever. It is rather delicate material and it is rare to find a rattler in the wild with more than a half dozen or so beads on it. A new bead is added at each shed (not once a year which is a common myth). Cheers, Bryan Australian Venom & Toxin Database http://www.uq.edu.au/~ddbfry/index.html
Try the links in the MadSci Library for more information on Zoology.