 In the latter case, the call is usually dominated by a certain harmonic ("dominant" frequencies are those present at higher intensities than other harmonics present in the call).A single echolocation call (a call being a single continuous trace on a sound spectrogram, and a series of calls comprising a sequence or pass) can last anywhere from 0.2 to 100 milliseconds in duration, depending on the stage of prey-catching behavior that the bat is engaged in.For example, the duration of a call usually decreases when the bat is in the final stages of prey capture – this enables the bat to call more rapidly without overlap of call and echo.