It's a spooky sound.  Sitting out next to the telescope and hearing a deer being killed in the neighbor's yard leaves a person feeling a bit exposed.  I still prefer the four legged neighbors rather than the two legged variety!  

There have been a number guys in the local astronomy club using the darker regional parks who have had experiences with the local mountain lions.  For whatever reason a lion approached the groups after dark and let out a few big cat howls.  The call of the wild was followed by a rapid packing of vehicles and calling it a night.