here ya go..
http://waldo.jaquith.org/audio/mystery-animal.mp3
it's not exactly the most comforting noise to hear at night.. and trust me.. they can get more blood curdling than that. a few times i swore it was a girl screaming.. but the more unpleasant bloody gurgling scream. ofcourse he only times i've heard this thing i was out alone at 3am. (usually i have some one with me).
tell ya one thing.. it wakes you right the heck up...