Prusten...

If you come face to face with an uncaged tiger there is only one sound you want to hear. Prusten. This rattling chuffing or snorting sound signifies a friendly greeting from one tiger to another. In other words, "Hi, I respect you, and I'm not going to kill you." Captive tigers have been known on rare occasions to use prusten with their keepers as a sign of affection. On the other end of the spectrum, a threatened tiger, one that is making up its mind about who you are, sounds like this.

Chances are, if you come face to face with a tiger, prusten will not be on the menu. The same can not be said for you. In fact, tigers always kill in silence, so your ears' final meal will probably go something like this.

("Rosie and Friends" by Paul Gachot)