What Is a Sound Spectrogram?
When researchers study sounds, it's really helpful to draw pictures of the sounds, especially if we can't hear them.

A sound spectrogram is like a voice print. It is a visual representation of the changes in frequencies, or pitches, over the course of a vocalization. The computer acts like a prism for sound to separate out the different frequencies so we can study them. The intensity, or loudness, of the sound is represented by how dark it is, so you can tell which pitches are emphasized at which times in the call.