Fig. 4
From: Nocturnal “humming” vocalizations: adding a piece to the puzzle of giraffe vocal communication
Log-log plot of average F0 for various mammals (n = 15) versus vocal fold length. The linear model predicts that the giraffe’s 41.45 mm [21] vocal fold should result in a mean F0 of ~50 Hz (log10 F0 (Hz) = −1.43 × log10 vocal fold length (mm) + 4.01). The mean fundamental frequency (indicated by the orange sun) of the recorded giraffe humming vocalizations was 92.01 ± 25.78 Hz, ranging from 35 to 144 Hz. (adapted from Fletcher [53] and Charlton et al. [52]). Data were taken from: [11, 35, 49, 50, 54–66]