Untitled Sighting

On two occasions in the last summer, my dad and I have heard what could only be described as a long, drawn out yowl.  Not like a coyote (wooooooo), but more waaaayoooahoooo), sounds stupid, but that's the best I can describe it.  Kind of harsh, too.  We heard it close by our campsite, and heard something moving.  When I shone my flashlight in the area, it stopped and sounded like it moved away.  To my knowledge, when a coyote howls, he gets answered, and doesn't just stop suddenly.  It would seem like it(?) was trying to communicate something.  A warning? surprise?  I don't know.  The second time, it was only my dad that heard it.  Both times, it stopped after we "investigated"(read, shined all the lights around in Holy terror)  There was never any evidence of what it was, and in the daylight was written off as a coyote.  But after hearing some of those sounds, the way these were "articulated" convinces me it wasn't.  P.S., it definitely was not a bear, I know what they sound like, dogs and coyotes also.