Fig. 1. Behavioral audiogram of the greater horseshoe bat Rhinolophus
ferrumequinum (Long and Schnitzler,
1975). The resting frequency (RF) is normalized to 80 kHz. The
frequency ranges over which Doppler-shift-compensation behavior was tested are
indicated in dark (Doppler shifts above RF) and light (Doppler shifts below
RF) gray shading. Within these ranges, two examples are given for the
intensity ranges tested. The numbers of playback signals analysed for this
graph were 512 for positive and 537 for negative Doppler shifts. The lower and
upper ends of the boxes indicate the twenty-fifth and seventy-fifth
percentile, respectively, with a broken horizontal line at the median. Error
bars indicate the tenth and ninetieth percentiles and squares indicate
outliers. The frequency range just above RF where thresholds reach very low
levels is also referred to as the `auditory fovea' (short horizontal bar
beneath the abscissa) (Schuller and
Pollak, 1979). Note that the difference between the medians of the
intensity ranges tested for positive and negative Doppler shifts corresponds
approximately to the difference in the hearing threshold for these frequency
ranges.
