The fun of recording nature sounds (and not filming it!)

Do you know what the sound of a fox calling sounds like? I didn’t (either) until I played an audio recording I made somewhere in the south of the Netherlands in a forest. But first, when playing the raw file back through my headphones, for a moment I got the shivers as I clearly heard a scream and thought I captured some sort of nocturnal slaughter, like a girl was screaming for her life.