Fig. S1 (PDF File) Psychometric functions obtained at 14 frequencies in water for Hawaiian monk seal Kekoa, with percent correct detection on signal-present trials (y-axis) shown as a function of sound pressure level (dB re 1 Pa, x-axis). Probit analysis was applied to fit these functions to the proportion of correct detections at each stimulus level presented during testing (5-7 SPLs and 38-53 trials per frequency; data from three staircase sessions). Threshold was measured using an inverse prediction, and is denoted here by the dashed line at the sound pressure level corresponding to 50% correct detection.
Audio Files Audio S1. Exemplars of the six underwater call types and one vocal bout produced by Hawaiian monk seal Kekoa at Long Marine Laboratory, as shown in Figure 3.
Audio S2. Exemplars of six underwater call types and one vocal bout produced by Hawaiian monk seal Ho‘ailona at Waikiki Aquarium.
Video Files Video S1. Video exemplar of underwater auditory testing with Hawaiian monk seal Kekoa. This video clip illustrates a portion of a testing session to evaluate underwater hearing sensitivity at 400 Hz.
Video S2. Video footage documenting underwater acoustic behavior in wild Hawaiian monk seals. These examples provide informal evidence of underwater communication in this species.